1

GCSE CHEMISTRY (COMBINED) HIGHER REVISION (revised)

Name:…………………………………………………………………………………………………………….

P1 & P2

Summary sheets 3 Parts of an atom

4 Metallic and ionic bonding

5 Covalent bonding

6 Calculations

P1

Summary sheets 7 States and separation

8 Acids

9 Electrolysis

10 Extraction of metals

P2 Summary sheets 11 Groups

12 Energy & rates of reaction

13 The Earth’s atmosphere and hydrocarbons

P1 & P 2 Skills

14 Balancing equations

15 Writing balanced equations

16 Writing a plan

17 Significant figures & calculating rate

Atomic Structure 18-19 Revision Questions

20-22 Exam Questions

Ionic Compounds 23-23 Revision Questions

24 6 mark – electrical conductivity

25 6 mark – ion formation

Molecular

Compounds

25-26 Revision Questions

28-29 Exam questions – Ionic & Molecular

Calculation

Practice

30-31 Calculation help sheet

32-33 Calculation Practice (1)

34-35 Calculation Practice (2)

P1 Separation 36-38 Revision Questions

39-41 Exam Questions

42-43 Core Practical – Investigate the composition of inks

using simple distillation and paper chromatography

Acids 44-45 Revision Questions

46 Titrations

47-49 Exam Questions

50 Core Practical – Investigate the preparation of pure,

dry, hydrated crystals of copper sulphate starting

from copper oxide.

51 Core Practical – Investigate the change in pH on adding

calcium hydroxide or calcium oxide to a fixed volume of

hydrochloric acid

Electrolysis 52-53 Revision Questions

54-55 Core Practical – Investigate the electrolysis of copper

sulphate solution using inert and copper electrodes.

56-58 Questions

Metals 59-60 Revision Questions

2

61-64 Exam Questions

P2 Groups 65-66 Revision Questions

67 6 mark – displacement reactions

68-69 Exam questions

Rates of Reaction 72-75 Revision Questions

76 6 mark – reaction rates

77-80 Exam questions

81-82 Core Practical – Investigate the effect of changing the

conditions of a reaction by measuring the production of

hydrogen and a colour change with sodium thiosulphate

solution

Fuels and Earth 83-84 Fuels and Earth Science

85-87 Exam Questions

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SKILLS – BALANCING EQUATIONS

1. ……..Al + ……….O2 2Al2O3

2. ……….Cu + O2 …….CuO

3. 2CH4 + ………O2 2CO + ……….H2O

4. Zn + ……..HCl ZnCl2 + H2

5. CaCO3 + ……….HCl CaCl2 + ………………..+ ……………………….

6. Fe2O3 + 3C ………….Fe + …………CO2

7. Complete the balanced equation for the reaction of butane, C4H8 with oxygen to form

carbon monoxide, CO and water.

C4H8 + 4O2

SKILLS – WRITING BALANCED EQUATIONS

1. Carbon monoxide reacts with oxygen, O2 to form carbon dioxide . Write the balanced

equation for this reaction.

2. The decomposition of hydrogen peroxide H2O2 produces oxygen and water. Give the

balanced equation for this reaction.

3. Zinc oxide, ZnO, reacts with dilute hydrochloric acid to form zinc chloride, ZnCl2 and

water. Write the balanced equation.

4. Write the balanced equation for the reaction of copper with oxygen to form copper

oxide CuO.

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5. Iron is extracted from iron oxide Fe2O3 by heating iron oxide with carbon to form iron

and carbon dioxide. Write the balanced equation.

6. Hydrocarbons react in excess oxygen to form carbon dioxide and water. Write the

balanced equation for the reaction of heptane C7H16 with excess oxygen.

7. Pentane, C5H12 burns completely in air to form carbon dioxide and water. Write the

balanced equation.

8. Copper chloride CuCl2 reacts with potassium hydroxide KOH to form copper hydroxide

Cu(OH)2 and potassium chloride. Write the balanced equation.

9. Hydrogen,H2 reacts with oxygen, O2 to form water under appropriate conditions.

Write the balanced equation.

10. Write the balanced equation for the reaction of hydrochloric acid with sodium

hydroxide.

11. Sulfur dioxide reacts with rainwater to form sulphurous acid, H2SO3. Sulfurous acid is

oxidised by oxygen in the air to form sulphuric acid. Write the balanced equation for

the oxidation of sulphurous acid by oxygen.

12. Calcium carbonate reacts with dilute hydrochloric acid to produce calcium chloride,

carbon dioxide and water. Write the balanced equation for this reaction.

SKILLS – IDENTIFY X

1. C12H26 C2H6 + C6H12 + X

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SKILLS – WRITING A PLAN

What are you changing?

What are you measuring?

What are you using to make the measurements?

What have you kept the same?

Marble chips (calcium carbonate) react with hydrochloric acid to produce carbon dioxide.

Calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide

Describe how you could use marble chips and a solution of hydrochloric acid to show that

changing the temperature of the hydrochloric acid changes the rate of this reaction.

Marble chips (calcium carbonate) react with hydrochloric acid to produce carbon dioxide.

Calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide

Describe how you could use marble chips and a solution of hydrochloric acid to show that

decreasing the concentration of the hydrochloric acid changes the rate of this reaction.

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SKILLS – SIGNIFICANT FIGURES

Give the following numbers to 2 significant figures:

23.12

5.667

0.356

45.58

Give the following numbers to 3 significant figures

46.789

5.689

0.1234

55.88

Give the following numbers to 2 decimal places:

23.156

23.557

23.412

SKILLS – CALCULATING THE RATE OF A REACTION

Calculate the average rate of reaction in volume of gas per second in the first 20 seconds

Draw a tangent and calculate the actual rate of reaction at 20s.

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ATOMIC STRUCTURE

Describe how the Dalton model of an atom has changed over time.

Complete table:

mass charge Position

Proton

Neutron

Electron

Explain why atoms contain equal numbers of protons and electrons

Compare the size of nucleus of an atom to the overall size of the atom.

State where most of the mass of an atom is concentrated

Describe the mass number of an atom

Describe the atomic number of an atom

What is unique about each element?

What is an isotope?

If an atom has an atomic number of 9 and a mass number of 19 give the number of

protons, electrons and neutrons.

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Calculate the relative atomic mass of chlorine if the relative abundance of carbon-13 is

21% and of carbon-12 79%.

How did Mendeleev arrange the elements at the time?

How did Mendeleev use his table to predict the existence and the properties of some

elements not then discovered?

Explain how you can use the atomic number to find the position of an element in the

periodic table.

Give the name for the rows in the periodic table.

Give the name for the columns in the periodic table. Why were some elements placed in

the same column?

Where are the metals and non-metals in the periodic table?

Give the rules for finding the electron configuration of an element

Maximum number of electrons in the first shell =

Maximum number of electrons in the second shell =

Maximum number of electrons in the third shell =

If an element has the electron configuration of 2.8.5 what does this tell you about the

position of the element in the periodic table?

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1 There are about 90 natural elements, which scientists have classified in the periodic table.

The grid below represents an outline of the periodic table. The letters A to F represent the positions of six different

elements in the table.

aWhich two letters represent elements that are metals? _________ _________ (2)

b Which two letters represent elements that have the same number of electrons in the outer shell of their atoms?

________ ________ (2)

cWhich two letters represent elements that have the same number of electron shells in their atoms?

________ ________ (2)

2 a Complete the table below with information about the three subatomic particles.

d Name of particle Charge Relative mass Where found in atom

proton 1 inside nucleus

electron -1 /negligible orbiting the nucleus

neutron 0 1

(2)

b An atom of oxygen has an atomic number of 8 and a mass number of 18.

i Complete the diagram on the right by drawing electrons

in the appropriate places to show the electron

configuration of oxygen.

(2)

ii Give the electron configuration of an oxygen atom

____________ (1)

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3 a The element boron has two isotopes, boron-10 and boron-11.

Complete the table below with the missing information about these isotopes of boron.

Isotope Atomic number

Mass number

Number of ...

protons neutrons electrons

boron-10 5 10 5 5

boron-11 5 11 5 5

(2)

b Describe, in terms of protons and neutrons in atoms, what is meant by the term ‘isotope’.

(2)

c Boron and aluminium are both found in group 3 of the modern periodic table.

i State why these elements are in the same group in the modern periodic table.

(2)

ii Suggest what this tells you about the chemical properties of the two elements.

(1)

4 a Mendeleev left gaps in his periodic table, putting question marks in for the elements with atomic masses

68 and 70.

iii Why did Mendeleev leave gaps in his first periodic table?

(1)

iv Give two ways in which Mendeleev ordered the elements in his periodic table

(2)

b How are the elements ordered in the modern periodic table?

(1)

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5 The diagram below shows a model of a lithium atom.

a This lithium atom can be represented in the form 73Li. State the number of protons and neutrons in the nucleus

of a lithium atom.

(2)

b Atom A has a mass number of 239 and an atomic number of 93.

v State the number of protons, neutrons and electrons in Atom A.

(3)

6 The relative atomic mass of an element can be calculated from data on isotopic abundance.

a Calculate the relative atomic mass of copper, which has two isotopes: 69% is 63Cu, 31% is 65Cu

Show all of your working in the box below.

(2)

b The element boron has 2 isotopes: boron-10 and boron-11 – it has a relative atomic mass of 10.8

What does this tells us about the relative abundance of the two isotopes of boron?

(1)

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IONIC COMPOUNDS

What is an ion?

How do ions form?

Why do ions form?

What is the name for a positive ion?

What is the name for a negative ion?

Draw a dot and cross diagram to show the bonding in sodium chloride, NaCl. Sodium has an

electron configuration of 2.8.1. Chlorine has an electron configuration of 2.8.7.

Describe the structure of an ionic compound

Do ionic compounds have high or low melting points? Explain

When do ionic compounds conduct electricity? Explain

What does the ending IDE usually mean in an ionic compound?

What does the ending ATE usually mean in an ionic compound?

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Give the formulae of the following compounds have been given their ions.

Ions : O2-, SO42-, CO3

2-, Cl-, Br-, NO3-, Mg2+, Ca2+ Na+

Magnesium oxide

Calcium Sulphate

Sodium oxide

Magnesium chloride

Calcium nitrate

Magnesium bromide

Sodium chloride

Electrical conductivity of ionic compounds (H) Explain the difference in the ability of solid sodium chloride and molten sodium chloride to conduct electricity in terms

of their structures. (6)

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C2 Key Assessment Task Ion formation (H)

Magnesium has an electronic configuration of 2.8.2. Oxygen has an electronic configuration of 2. Explain, in terms of their electronic configurations, how magnesium and oxygen atoms react to form the ionic compound magnesium oxide, MgO, and include a description of the structure of solid magnesium oxide. (6) ……………………………………………………………………………………………………………………………………………………………………………

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MOLECULAR COMPOUNDS

What is a covalent bond?

Draw the dot and cross of H2

Electron configuration of H = 1

Draw the dot and cross of HCl

Electron configuration of H = 1, Cl= 2.8.7

Draw the dot and cross of CH4

Electron configuration of H = 1, C=2.4

Draw the dot and cross of H2O

Electron configuration of H = 1, O= 2.6

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Diamond - describe the bonding

Explain why it doesn’t conduct electricity

Give a use:

Graphite - describe the bonding.

Explain why it conducts electricity.

Give a use:

METALS

Label the diagram Explain why metals are malleable

Explain why metals conduct electricity

Draw the dot and cross of O2

Electron configuration of O = 2.6

Draw the dot and cross of CO2

Electron configuration of C = 2.4, O=2.6

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Sciences SC 5/6/7 BONDING

1. Many substances exist as molecules.

(a) The diagram shows the outer shell electrons in a molecule of methane CH4

Each hydrogen atom is bonded to the carbon atom by a covalent bond.

Give the meaning of the term covalent bond

……………………………………………………………………………….(2)

(b) Methane is a typical simple molecular, covalent compound. A property

of methane is that it has:-

A A high melting point

B It is a good conductor of electricity

C There are weak bonds in its molecule

D It has a low boiling point

2 (a). The electron configuration of oxygen (atomic number 8) is 2.6

Give the electronic configuration of carbon (atomic number 6)……………………………..

(b) Draw a dot and cross diagram of a molecule of carbon dioxide. Show the outer electrons only.

3.

sodium Sulphur

Metal or non metal metal Non-metal

Symbol Na S

Atomic number 11 16

Sodium sulphide is an ionic compound. Describe in terms of electron transfer how sodium atoms react with sulphur

atoms to form sodium sulphide. Your description should include the charges on the ions formed (4).

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4. The structures of diamond and graphite are shown below.

(i) State the maximum number of covalent bonds formed by a carbon atom in a diamond crystal ………………

(ii) Which of the following statements about diamond and graphite is true?

A – they are both good conductors of electricity

B – they are both soluble in water

C – they both cut glass

D – they both have high melting points

5. Oxygen is a simple molecular, covalent substance. The electronic configuration of oxygen is 2.6. Draw a dot and

cross diagram for a molecule of oxygen, O2. Show the outer electrons only.

6. Hexane is a covalent compound containing simple molecules. It has a low boiling point. Explain why it has a low

boiling point.

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SUMMARY OF METHODS FOR CALCULATIONS

1. Calculate Relative Formula Mass

You need to add up the masses of all the atoms in the formula.

2. Give empirical formula from molecular formula

You need find the simplest ratio. Decide whether each number can be divided by a common number

3. Calculate Empirical Formula

Calculate Mass (no of moles)

RAM

Divide by the smallest number

Give the empirical formula

4. Calculating theoretical mass

1. Calculate number of moles of the known (Mass/RAM)

2. Look at the ratio of the known:unknown

3. Rearrange the formula and use mass = moles x RAM

5. Calculate concentration in gdm-3

Convert cm3 into dm3 by dividing by 1000

Use concentration = mass

Volume (in dm3)

6. Calculate Rf values

Rf value = distance moved by solute

Distance moved by solvent

Rf values CANNOT be >1.

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7. Calculate number of moles

Number of moles = mass

RAM

8. Calculate the number of particles from number of moles

Number of particles = number of moles x Avogadro’s constant

You are given Avogradro’s constant of 6.02 x 1023

9. Calculate the number of particles from a mass

Calculate the number of moles first.

Then use number of particles = number of moles x Avogadro’s constant.

10. Calculating a balanced equation

This is the same method as empirical formula but instead of using the atoms of elements you need to use the fomula

in the equation.

Calculate number of moles of the substances

Divide by the smallest number

These values then give you the balancing numbers in an equation.

11. Identifying the limiting reactant.

Calculate the number of moles of one of the substances.

Then use the ratio to find the number of moles you need of the other.

Then calculate the number of moles of the other substance and compare to how much you need.

12. Calculating the energy change in a reaction

Calculate the energy of the reactants (LHS of the equation)

Calculate the energy of the products (RHS of the equation)

LHS – RHS

13. Calculate relative atomic mass of a samples.

Relative atomic mass = (% abundance of A x atomic mass of A) + (% abundance of B x atomic mass of B )

100

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REVISION CALCULATION QUESTIONS - COMBINED (1)

1.Calculate the relative formula mass

What is the relative formula mass of Ba (OH)2? (relative atomic masses: Ba=137, O=16, H=1)

2. Give the empirical formula from the molecular formula

If a sample has the molecular formula of C2H4 what is the empirical formula?

3.Calculate Empirical formula

A sample of nitrogen oxide contains 4.0g of nitrogen and 9.2g of oxygen. Calculate the empirical formula (relative

atomic masses: N=14, O = 16).

4. Calculating theoretical masses

CaCO3 + H2SO4 CaSO4 + H2O + CO2

If 55g of CaCO3 reacts what mass of CaSO4 is produced ? (relative atomic masses: Ca=40, C=12, O = 16, H =1, S=32)

5. Calculate concentrations in g dm-3

4.1g of sodium chloride is dissolved in 50cm3 of water. Calculate the concentration of the sodium chloride solution in

g dm-3.

6. Calculate Rf values in chromatography

If the solvent moves 10cm and the solute moves 6cm calculate the Rf value.

7. Calculation of number of moles (HIGHER ONLY)

How many moles are there in 42g of magnesium (relative atomic mass: Mg = 24)? Give the answer to 2 significant

figures.

8. Calculate number of particles (HIGHER ONLY)

Avogadro’s constant is 6.02 x 1023. How many potassium atoms are there in 0.8 moles of potassium?

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9.Calculate number of particles (HIGHER ONLY)

Avogadro’s constant is 6.02 x 1023. How many potassium atoms are there in 22 g of potassium? (relative atomic

mass: K=39)

10. Working out the balanced equation from given masses (HIGHER ONLY)

If 10.4g of sulphur reacts with 5.2g of O2, oxygen to form a sulfur oxide, use the masses to determine the LHS of the

balanced equation. (relative atomic masses: S=32, O=16)

11. Calculating limiting reactant (HIGHER ONLY)

Mg +2HCl MgCl2 + H2

If 1.3 g of magnesium reacts with 18.5g of hydrogen chloride, which is the limiting reactant? (relative atomic

masses: Mg = 24, Cl=35.5, H=1)

12. Calculate the energy change for the reaction using bond enthalpies

2H2 + O2 2H2O

Bond Energy KJ/mol

H-H 436

O=O 498

O-H 464

13. Calculate the Relative Atomic Mass of an element from the % abundances13. Calculate the Relative Atomic

Mass of an element from the % abundances

A sample contains 85.4% of carbon-12 and 14.6% of carbon-13. Use this information to calculate the relative atomic

mass of boron.

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REVISION CALCULATION QUESTIONS COMBINED (2)

1.Calculate the relative formula mass X

Calculate the relative formula mass of magnesium nitrate, Ca(NO3)2? (relative atomic masses: Ca = 40, N=14,O=16)

2. Give the empirical formula from the molecular formula

If a sample has the molecular formula of N3O6 what is the empirical formula?

3.Calculate Empirical formula

A sample of calcium iodide contains 0.2g of calcium and 1.3 g of iodine by mass. Calculate the empirical formula of

calcium iodide (relative atomic masses: Ca=40, I = 127).

4. Calculating theoretical masses

CuCO3(s) CuO (s) + CO2 (g)

35g of pure copper carbonate is decomposed completely. Calculate the maximum mass of the solid produced

(relative atomic masses: Cu=63.5, C=12, O = 16). Give your answer to 2 sig fig.

5. Concentrations in g dm-3

A potassium iodide solution contains 5.3 g of potassium iodide in 50cm3 of water. Calculate the concentration of the

potassium iodide solution in g dm-3.

6. Calculate Rf values in chromatography

If the solvent moves 15cm and the solute moves 10cm calculate the Rf value.

7. Calculation of number of moles (HIGHER ONLY)

Calculate the number of moles of sodium in 42g (relative atomic mass: Na= 23)? Give the answer to 2 significant

figures.

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8. Calculate number of particles (HIGHER ONLY)

Calculate the number of atoms in 0.6 moles of potassium? Avogadro’s constant is 6.02 x 1023)

9.Calculate number of particles (HIGHER ONLY)

Calculate the number of atoms in a 25g sample of potassium? (relative atomic mass: K=39) (Avogadro’s constant is

6.02 x 1023)

10. Working out the balanced equation from given masses (HIGHER ONLY)

In an experiment, 11.2g of iron reacts exactly with 76.2g of iodine, I2. Determine the balanced equation for the

reaction between iron and iodine. (Relative atomic masses: Fe=56, I=127)

11. Calculating limiting reactant (HIGHER ONLY)

2Li +2HCl 2LiCl + H2

If 3.5 g of lithium reacts with 16.5g of hydrogen chloride, which is the limiting reactant? (relative atomic masses:Li =

7, Cl=35.5, H=1)

12. Calculate the energy change for the reaction using bond enthalpies

2CH4 + 2O2 2CO2 + H2O

Bond Energy KJ/mol

C-H 413

O=O 498

O-H 464

C=O 799

13. Calculate the Relative Atomic Mass of an element from the % abundances

A sample contains 19.7% of boron-10 and 80.3% of boron-11. Use this information to calculate the relative atomic

mass of boron.

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SEPARATION

Describe the arrangement, movement and the relative energy of particles in a solid

Describe the arrangement, movement and the relative energy of particles in a liquid

Describe the arrangement, movement and the relative energy of particles in a gas

Give the names of the interconversions from solid -> liquid -> gas

Give the names of the interconversions from gas -> liquid -> solid

If a substance has a melting point of -20oC boiling point of 16oC what is its state at room

temperature 25oC?

If a substance has a melting point of -20oC and boiling point of 100oC what is its state at

room temperature 25oC?

What is the difference between the melting points of pure substances and mixtures

Heating curves. Describe the changes that are happening in the following curve.

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What is simple distillation used for?

Draw a labelled diagram of distillation

Describe the risks of using distillation to separate an ethanol-water mixture.

Draw a labelled diagram of filtration.

What is filtration used for?

Describe crystallisation.

Draw a diagram to show how to produce a chromatogram

Give the name of the solvent in chromatography

Give the name of the paper in chromatography

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Why do some compounds move to a higher position on the chromatography paper than

others?

Why do some dots not move on the chromatography paper?

Calculate the Rf value of a compound if the dot of the solute moves 4cm and the solvent

moves 6cm. Leave your answer to 2 significant figures.

What does potable mean?

How can river and waste water be made potable?

Who can sea water be made potable?

Why can’t sea water be used for chemical analysis?

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SEPARATION EXAM QUESTIONS

1.Substances can be pure or they can be mixtures. Which of the following is a mixture?

A Chlorine

B Sodium

C Sodium chloride

D Sodium chloride solution

2. The table shows some mixtures to be separated and some possible methods of separation. Place a tick in one box

in each row of the table to show the best method to separate the first named substance from each of the mixtures.

Substance to separate

Method of separation

Crystallisation Filtration Simple distillation Fractional distillation

Sand from a mixture of sand and sodium chloride solution

Copper sulphate crystals from copper sulphate solution

Useful liquids from crude oil

3. Paper chromatography was used to separate a mixture of blue and red inks. A spot of the mixture was placed on

chromatography paper as shown below.

(a) Give a reason why the start line is drawn in pencil rather than ink.

……………………………………………………………………………………………………………………………………………………………………………(1)

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The chromatography paper with the mixture on it was placed in a beaker with the bottom of the paper in the water.

Complete the diagram below showing the position of the chromatography paper with the spot of mixture at the start

of the experiment.

The chromatography was carried out and the result is shown below.

(b)The blue spot had moved 14.5cm and the solvent front had moved 15.3cm. Calculate the Rf value of the

substance in the blue spot. Give the answer to 2 significant figures.

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(c )If a spot does not move from the original pencil line, what information does this give about the substance in the

spot?

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4. The table shows the boiling point and melting point of naphthalene. Give the physical state of naphthalene at

225oC.

Melting Point oC Boiling Point oC

Napthalene 78 218

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5. A student heated a substance in a solid state. She measure the temperature of the substance every minute until a

few minutes after it melted. The student identified three different stages in how the substance looked. The graph

below shows the results of her experiment.

(a)Explain whether the results show the substance was a mixture or a pure substance.

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(b) What is the name given to stage B ………………………………………………………………………………………………………………..

6. The diagram below shows the three stages to treat fresh water to make it potable.

(a) State what happens during sedimentation ……………………………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………………..

(b)Explain why the water is not pure after the filtration stage

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(c ) Give a reason why the chlorination stage is necessary

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CORE PRACTICAL - Investigating Inks

Answer

What is the practical about?

What is the process called?

Name a hazard and a way to reduce the risk

What temperature does water boil at ?

What is the name given to the process when water vapour becomes a liquid?

Why is ice used ?

Draw particles diagrams to show the arrangement of particles in a solid, liquid and gas

SOLID

LIQUID

GAS

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PRACTICAL 2 - Chromatography

Section Answer

What is the practical

about?

Give the name of the

process

Describe how to create a

chromatogram

1.

2.

3.

Calculate the Rf value of

the purple spot

Calculate the Rf value of

the blue spot

If a spot on the pencil

line doesn’t move what

does it tell you about the

substance?

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ACIDS MAX TAYLOR

What does an acid contain?

H+

What ions do alkalis contain?

OH-

What is the pH of a neutral solution?

7

When the pH of an acid reduces from 2 to 1 what does this say about the concentration?

X10

H What is meant by a dilute solution compared to concentrated solution?

Doesn’t contain many ions

H What is meant by a weak acid?

Partially ionises

H What is meant by a strong acid?

Totally ionises

What is a base?

Reacts with an acid

Complete the word equation and give the balanced equation

Hydrochloric acid + magnesium

Magnesium chloride + hydrogen

Complete the word equation and give the balanced equation

Nitric acid + calcium oxide calcium nitrate + water

Complete the word equation and give the balanced equation

Sulfuric acid + magnesium hydroxide magnesium sulphate + water

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LUCY

Complete the word equation and give the balanced equation

Hydrochloric acid + magnesium carbonate

Magnesium chloride + carbon dioxide + water

What is the test for hydrogen gas?

Lit splint makes squeaky pop

What is the test for carbon dioxide?

Bubble into limewater and turns cloudy

What is the name of the reaction between an acid and alkali?

Neutralisation

What is the ionic equation for a neutralisation reaction?

H+ + OH- H2O

46

TITRATIONS

List the equipment used in a titration –state what it is used for

-

-

-

-

-

-

-

INDICATORS IN A TITRATION

Colour in acid Colour in alkali

Methyl Orange

Phenol Phthalein

Why can’t Universal Indicator be used in a titration?

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

47

Questions on acids

Q1. Calcium nitrate solution can be made by adding solid calcium carbonate to dilute nitric acid in a beaker. The solid calcium carbonate is added until some remains at the bottom of the beaker.

(i) After this reaction the liquid in the beaker is

(1)

A acidic

B alkaline

C neutral

D pure water

(ii) Explain why the calcium carbonate is added until some solid remains at the bottom of the beaker.

(2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

(iii) Write the balanced equation for the reaction between calcium carbonate and nitric acid to form calcium nitrate, Ca(NO3)2.

(3)

.............................................................................................................................................

Q2. A solution of hydrochloric acid has a pH of 1.

Explain the pH change when 10 cm3 of this acid is diluted with water to make 100 cm3 of solution.

(2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

Q3. A student carried out an experiment to see how reactive different metals are when they are placed in dilute hydrochloric acid. A sample of each metal was placed in a separate test tube of acid. In the experiment, the student used the same amount of each metal in a finely powdered form.

State two factors, concerning the hydrochloric acid, which should also be controlled to produce valid results.

(2)

1 ..........................................................................................................................................

.............................................................................................................................................

2 ..........................................................................................................................................

.............................................................................................................................................

48

Q4. A student has been asked to investigate how the pH changes when calcium oxide is added, a little at a time, to dilute hydrochloric acid. Describe how the student should carry out this investigation.

(3)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

Q5. A strong acid reacts with a strong alkali to form a neutral solution.

Write the ionic equation for this reaction.

(2)

.............................................................................................................................................

Q6. A student carried out an experiment to see how reactive different metals are when they are placed in dilute hydrochloric acid.

A sample of each metal was placed in a separate test tube of acid.

When zinc reacts with dilute hydrochloric acid, a gas is given off and zinc chloride is formed.

(i) Which gas is given off?

A carbon dioxide

B chlorine

C hydrogen

D oxygen

(1)

(ii) What is the formula of zinc chloride?

A ZnCl

B Zn2Cl

C ZnCl2

D Zn2Cl2

(1)

Q7. Some acids such as hydrochloric acid are described as strong acids. Some acids such as ethanoic acid are described as weak acids.

(i) Explain the difference between a strong acid and a weak acid. (2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

(ii) Give a reason why adding hydroxide ions to an acid solution leads to an increase in pH. (1)

.............................................................................................................................................

.............................................................................................................................................

49

Q8. Carbon dioxide can be formed by the reaction of magnesium carbonate, MgCO3, with dilute hydrochloric acid. Write the balanced equation for this reaction.

(3)

.............................................................................................................................................

Q9. The salt zinc nitrate can be made by reacting zinc oxide, ZnO, with dilute nitric acid, HNO3.

Write the balanced equation for this reaction.

(2)

.............................................................................................................................................

Q10. Sodium hydroxide, NaOH, can be reacted with dilute sulfuric acid, H2SO4, to form sodium sulphate and water. Write the balanced equation for this reaction.

(2)

.............................................................................................................................................. Q11. (a) A titration is used to determine the exact volumes of sulfuric acid and sodium hydroxide solution that neutralise each other. 25.00 cm3 of sodium hydroxide solution is put into a conical flask and a few drops of indicator solution are added. The sulfuric acid is added slowly from a burette until the indicator changes colour when all the sodium hydroxide is just neutralised.

(i) State what is used to measure out 25.00 cm3 of sodium hydroxide solution. (1)

.............................................................................................................................................

(ii) State the name of an indicator that could be used and the colour change seen in this titration.

(3)

Indicator .............................................................................................................................................

colour in sodium hydroxide solution ....................................................................................................

colour at end of titration .........................................................................................................................

50

CORE PRACTICAL - Preparing copper sulfate

Section Answer

What is practical about?

Give the 4 steps in the

method

M

S

F

E

Name the process when

the water is evaporated

to leave the crystals

Making a soluble salt from an acid and

insoluble reactant.

51

CORE PRACTICAL - Investigating Neutralisation

Section Answer

What is practical about?

Give the method

1.

2.

3.

How do you measure

the pH?

52

ELECTROLYSIS

What is an electrolyte?

What is electrolysis?

What is the name of the negative electrode?

What is the name of the positive electrode?

Which ions (cations or anions) move to the cathode?

Which ions (cations or anions) move to the anode?

What are the 2 ions present in water?

Electrolyte

Product formed at the anode Product formed at the cathode

Molten lead bromide

Molten sodium chloride

Acidified water

Sodium chloride solution

Sodium sulphate solution

Copper sulphate solution (inert electrodes)

53

At the anode: A sulphate solution doesn’t break down so Oxygen forms from Hydroxide in the water

At the cathode: The lest reactive element forms

O

I

L

R

I

G

In molten lead bromide, the Pb2+ forms Pb and Br2 forms from Br-. Complete the half equations. State which is

oxidised and which is reduced. Explain.

Pb2+

Br-

In molten sodium chloride, the Na+ forms Na and Cl2 forms from Cl-. Complete the half equations. State which is

oxidised and which is reduced. Explain.

Na+

Cl-

In acidified water, H2 forms from H+ and O2 forms from OH-. Complete the half equations. State which is oxidised and

which is reduced. Explain.

H+

OH-

In sodium chloride solution, H2 forms from H+ and Cl2 forms from Cl-. Complete the half equations. State which is

oxidised and which is reduced. Explain.

H+

Cl-

In sodium sulfate solution, H2 forms from H+ and O2 forms from OH-. Complete the half equations. State which is

oxidised and which is reduced. Explain.

H+

OH-

In copper chloride solution, Cu forms from Cu+ and Cl2 forms from Cl-. Complete the half equations. State which is

oxidised and which is reduced. Explain.

Cu+

Cl-

54

CORE PRACTICAL - Electrolysis of copper sulfate solution - using copper electrodes

Section Answer

What is practical about?

Which electrode increases in mass?

Explain the change in mas

Describe the relationship between the change in mass and the current

Give the half equation for the cathode

Give the half equation for the anode

55

CORE PRACTICAL - Electrolysis of copper sulfate solution - using inert electrodes

Section

Answer

What is the practical about?

Cooper is formed at the cathode. Give the half equation

Oxygen is formed at the anode. Give the half equation

56

ELECTROLYSIS QUESTIONS Q1. (i) When copper sulfate solution is electrolysed using inert electrodes, oxygen is formed at the positively charged anode. Explain how the oxygen is formed from ions in the solution.

(2)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

.............................................................................................................................................. Q2. The ions in sodium chloride solution are

sodium ions, Na+ chloride ions, Cl– hydrogen ions, H+ hydroxide ions, OH– Sodium chloride solution is electrolysed using a direct electric current. (i) Which of these ions will be attracted to the cathode during the electrolysis of sodium chloride solution?

Put a cross ( ) in the box next to your answer. (1)

A H+ ions only

B H+ and Na+ ions

C Cl– ions only

D Cl– and OH– ions (ii) Chlorine is one of the products of the electrolysis.

The half-equation for the production of chlorine is 2Cl– → Cl2 + 2e

Explain how the half-equation shows that chloride ions are oxidised. (2)

..............................................................................................................................................

.............................................................................................................................................. (iii) Suggest why the solution remaining at the end of the electrolysis is alkaline.

(1)

..............................................................................................................................................

.............................................................................................................................................. (iv) The electrolysis of sodium chloride solution does not produce metallic sodium.

State what change you would make to the electrolyte to obtain metallic sodium. (1)

..............................................................................................................................................

.............................................................................................................................................. Q3.(a) Copper sulfate solution was electrolysed using copper electrodes. The mass of each electrode was determined before it was placed in the solution.

57

The electrolysis was carried out for a period of time. The electrodes were removed, washed, dried and their masses redetermined. The table shows the masses of the electrodes before and after electrolysis.

Explain these results.

(3)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

............................................................................................................................................. (c) In an electrolysis experiment, oxide ions, O2−, form oxygen gas, O2.

Write the balanced half equation for the reaction. (2)

............................................................................................................................................. (d) Sodium chloride is an ionic compound. It contains sodium ions, Na+, and chloride ions, Cl−.

When molten sodium chloride is electrolysed, sodium metal and chlorine gas are formed. Describe how the sodium ions and chloride ions in solid sodium chloride are converted into sodium and chlorine by electrolysis.

(6)

.............................................................................................................................................

.............................................................................................................................................

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58

Q4.(a) Molten lead bromide is electrolysed.

(i) Complete the sentence describing the type of reaction.

(1) During the electrolysis the lead ions gain electrons at the cathode. The type of reactions in which metal ions gain electrons is called .....................................................

(ii) Complete the sentence by putting a cross ( ) in the box next to your answer. Molten lead bromide, rather than solid lead bromide, has to be electrolysed because

(1)

A ions can only move freely in molten lead bromide

B electrolysis is too fast in solid lead bromide

C molten lead bromide contains free electrons

D lead bromide has a very low melting point (iii) When molten lead bromide is electrolysed, a silver-coloured liquid is produced at the cathode and a red-brown gas is produced at the anode. Complete the word equation by showing the products formed when molten lead bromide is electrolysed. (2)

lead bromide → ..................................................... + .....................................................

Q5. Water decomposes into hydrogen and oxygen during electrolysis. A sample of water is electrolysed. The hydrogen and oxygen are collected separately. After 10 minutes the volumes of hydrogen and oxygen are measured.

Two further experiments are carried out, changing only one factor in each experiment. All other factors are kept the same. The table below shows the conditions and results for all three experiments.

Experiment Time (mins) Current (Amps) Volume of hydrogen (cm3)

Volume of oxygen (cm3)

1 5 0.50 20.0 10.0

2 10 0.50 40.0 20.0

3 5 0.75 30.0 15.0

Analyse this data to explain the effect of changing the time and the current on the volumes of hydrogen and oxygen produced.

59

EXTRACTING METALS AND EQULIBRIA

How are reactive metals found on Earth?

How are unreactive metals found on Earth?

What is oxidation in terms of oxygen?

What is reduction in terms of oxygen

How do you extract reactive metals such as aluminium from their ores?

How do you extract less reactive metals such as iron from their ores?

H Describe bacterial extraction

H Describe phytoextraction

What are the advantages of recycling metals?

What factors should you include in the lifetime assessment of a product?

60

What is meant by a dynamic equilibrium?

In the formation of ammonia where do the nitrogen and hydrogen come from?

What are the conditions of the Haber process?

H For the Haber Process, how will the position of dynamic equilibrium change with increased

temperature?

H For the Haber Process, how will the position of dynamic equilibrium change with increased

pressure?

H For the Haber Process, how will the position of dynamic equilibrium change with increased

concentration?

61

METAL EXTRACTION QUESTIONS Q1. Iron is extracted from iron oxide, Fe2O3. In the extraction process the iron oxide is heated with carbon to form iron and carbon dioxide. Write the balanced equation for this reaction.

(3)

.............................................................................................................................................

Q2. Complete the sentence by putting a cross ( ) in the box next to your answer.

The reaction for the extraction of aluminium from its ore involves (1)

A heating with carbon

B thermal decomposition

C reduction

D neutralisation Q3. The list shows some metals in order of reactivity.

(a) Aluminium and iron are extracted by reduction of their oxides.

State what is meant by reduction. (1)

.............................................................................................................................................

.............................................................................................................................................

(b) Electrolysis and heating with carbon are two methods of reduction.

Explain why aluminium needs to be extracted from its ore by electrolysis, rather than by heating with carbon.

(2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

62

Q4. Impure copper is purified by electrolysis using the apparatus shown.

(i) Give the name of the electrode which is made of pure copper.

(1)

.............................................................................................................................................

(ii) Describe how each electrode will have changed at the end of the electrolysis process.

(2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

(iii) Complete the sentence by putting a cross ( ) in the box next to your answer.

Cu2+(aq) + 2e− → Cu(s)

This half equation shows the process of (1)

A displacement

B oxidation

C redox

D reduction

(iv) Copper sulfate solution is the electrolyte used in this electrolysis process.

Explain how copper sulfate solution conducts electricity. (2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

63

Q5. When nitrogen and hydrogen react to form ammonia, the reaction can reach a dynamic equilibrium.

Explain what is meant by a dynamic equilibrium.

(2)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

.............................................................................................................................................. Q6. When nitrogen and hydrogen react to form ammonia, the reaction can reach a dynamic equilibrium.

In industry, the reaction between nitrogen and hydrogen is affected by the conditions used.

(i) The pressure used is 250 atmospheres. Explain how the use of a higher pressure would affect the equilibrium yield of ammonia.

(2)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

.............................................................................................................................................. (ii) The reaction between nitrogen and hydrogen to form ammonia is exothermic. The temperature used is 450°C. Explain how the use of a lower temperature would affect the equilibrium yield of ammonia.

(2)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

.............................................................................................................................................. (iii) Even at 450°C, the reaction is very slow. State what is used in industry to overcome this problem.

(1)

.............................................................................................................................................. Q7.(a) In the extraction of tin from tin oxide, tin oxide is heated with carbon.

Complete the sentence by putting a cross ( ) in the box next to your answer. When the tin oxide reacts with carbon to form the products

(1)

A tin is oxidised

B tin oxide is reduced

C carbon is reduced

D carbon dioxide is oxidised

64

(c) Metals are obtained from the Earth's crust by different methods. Some metals are found uncombined but others have to be extracted from their ores by electrolysis or by heating the ore with carbon. Explain, using aluminum, gold and iron as examples, how the method used to obtain the metal is related to its position in the reactivity series and to the cost of the extraction process.

(6)

.............................................................................................................................................

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65

GROUPS IN THE PERIODIC TABLE

What is the name for group 1 elements?

What is the name for group 7 elements?

What is the name for the group 0 elements?

Give 2 properties of alkali metals

Describe the reactions of lithium, sodium and potassium with water

Describe the pattern in reactivity of the alkali metals

Explain the pattern in reactivity of alkali metals

Give the colour and state of chlorine

Give the colour and state of bromine

Give the colour and state of iodine

Describe the pattern in physical properties of the halogens and use this to predict the

physical properties of astatine

66

Describe the chemical test for chlorine

Describe the reaction of chlorine, bromine and iodine with metals to form metal halides

Describe the relative reactivity of the halogens as shown by their displacement reactions

with halide ions in aqueous solutions.

H Explain why displacement reactions are redox reactions in terms of gain and loss of

electrons, identifying which are oxidised and which are reduced.

Explain the relative reactivity of the halogens

Explain why the noble gases are chemically inert

Explain why the uses of noble gases depend on their inertness, low density and low

flammability.

Describe the pattern in the physical properties of some noble gases and use this pattern

to predict the physical properties of other noble gases.

67

6 MARK QUESTION PRACTICE Chlorine, bromine and iodine are in group 7 of the periodic table. The order of reactivity of

these three elements can be shown by carrying out displacement experiments.

You are provided with

potassium bromide solution

potassium chloride solution

potassium iodide solution

bromine solution

chlorine solution

iodine solution

Describe how these solutions could be used to carry out experiments to show

the order of reactivity of bromine, chlorine and iodine, explaining how the results

would show the order of reactivity. You may use equations if you wish. (6) _____________________________________________________________________________________________________

_____________________________________________________________________________________________________

_____________________________________________________________________________________________________

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QUESTION PRACTICE

1 Look at the table of data below.

Group 0 density (g/cm3)

helium 0.00018

neon 0.0009

argon 0.0018

krypton 0.0038

Describe the trend in density down the group 0 elements.

___________________________________________________________________________________

________________________________________________________________________________ (1)

68

Estimate the density of xenon, the fifth group 0 element.

_____________________ g/cm3 (1)

2 The elements in group 1 of the periodic table are called the ‘alkali metals’.

a Describe the trend in reactivity down the group of alkali metals.

____________________________________________________________________ (1)

b The alkali metals react with water to produce an alkali and hydrogen gas.

c Complete the balanced equation below for the reaction between sodium and water.

d 2Na(s) + 2H2O(l) ___________(aq) + _______(g) (2)

e Compare and contrast the reactions of lithium and potassium with water.

___________________________________________________________________________________

___________________________________________________________________________________

________________________________________________________________________________ (2)

3 The balanced equation shows the displacement of bromine from sodium bromide solution using chlorine water.

Cl2(aq) + 2NaBr(aq) 2NaCl(aq) + Br2(aq)

a Write an ionic equation for this reaction in the box below. You should include ion charges in your equation and

omit spectator ions. You do not need to include state symbols.

(2)

b Explain why this displacement reaction is an example of a redox reaction.

___________________________________________________________________________________

___________________________________________________________________________________

________________________________________________________________________________ (2)

c Which one of the following pairs of solutions will react together? Tick one box.

A chlorine + sodium chloride

B bromine + potassium iodide

C iodine + lithium bromide

D bromine + sodium chloride (1)

69

QUICK TEST - GROUPS

1. Give the name of group 1 elements………………………………………………………………………………………………………………………..

2. Give the order of reactivity of group 1 elements?.....................................................

3. Give 3 observation when group 1 metal is added to water …………………………………………………………………......

................................................................................................. ................

4. Give the balanced equation for adding sodium, Na to water. …………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………………………………………..

5. Give the name of group 7 elements ……………………………………………………………………………………………………………………..

6. Give the order of reactivity of group 7 elements …………………………………………………………………………………………..

7. Complete the equation:

potassium bromide + chlorine

8. What would you observe in the above reaction and why ………………………………………………………………………………

……………………………………………………………………………………………………………………………………………………………………………………………….

9. Give the name of group 0 elements……………………………………………………………………………………………………………………….

10. Describe and explain the reactivity of group 0 elements…………………………………………………………………………….

………………………………………………………………………………………………………………………………………………………………………………………………..

70

RATES OF REACTION AND ENERGY CHANGES

1. Describe how you would use

the following practical to

determine the rate of reaction

between acid and magnesium

ribbon.

………………………………………………………

………………………………………………………

………………………

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

2. What improvement could you make to this practical to collect more accurate results?

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

3. In a reaction 50cm3 of gas is produced in 30 seconds, what is the rate of reaction?

4. If you increase temperature the rate of reaction …………………………………… . This is because the

particles have ....

5. If you increase the pressure the rate of reaction ……………………………………… . This is because the

particles …

6. If you increase the surface area (by making the substance a powder) the rate of

reaction………………………………….. This is because…

7. If you increase the concentration the rate of reaction …………………………………….. This is because….

8. A …………………………………… also increases the rate of reaction by ……………………………….

Mass of catalyst (g)

Time (s)

71

What are enzymes and where are they sometimes used?

Describe an exothermic reaction

Describe an endothermic reaction

Explain why some reactions are exothermic

Explain why some reactions are endothermic

Explain the term activation energy

Draw an energy profile diagram of an endothermic reaction. Add the activation energy

and label.

72

Draw an energy profile diagram of an exothermic reaction. Add the activation energy and

label.

QUESTION PRACTICE

Q1 (a) Calcium carbonate reacts with dilute hydrochloric acid. Complete the sentence by putting a cross ( ) in

the box next to your answer. (1)

In this reaction hydrochloric acid is

A precipitated

B displaced

C neutralised

D combusted

(b) The equation for the reaction is

The diagram shows the heat energy contained in the reactants and the heat energy contained in the products.

73

Use the diagram to explain why this reaction is as an exothermic reaction. (2)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

(c) If dilute hydrochloric acid is heated before calcium carbonate is added, the rate of reaction increases.

Explain, in terms of particles, why the rate of reaction increases.

(3)

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

..............................................................................................................................................

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Q2. Zinc is a metal. Zinc reacts with dilute hydrochloric acid to produce zinc chloride and hydrogen. Edward used this apparatus to investigate the speed of the reaction between zinc and dilute hydrochloric acid.

(i) Edward's results for 50 °C are shown on the graph.

Sketch a line on the graph to show the results that Edward should expect to obtain if he carried out the experiment to completion at 30 °C.

(2)

74

(ii) When zinc powder is used, instead of larger pieces of zinc, the reaction is faster. Explain, using ideas about particles, why the reaction is faster when zinc powder is used.

(2) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (iii) Balance the equation for the reaction of zinc with dilute hydrochloric acid by putting a number in the space provided.

(1) Zn + . . . . . . . . . . . . . HCl → ZnCl2 + H2

(iv) The reaction between zinc and dilute hydrochloric acid is exothermic. Explain, in terms of breaking and forming bonds, why this reaction is exothermic.

(3) .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. Q3. (a) A student investigated the rate of a reaction. The student investigated the reaction between zinc and dilute sulfuric acid. The products are zinc sulfate, ZnSO4, and hydrogen. (i) Write the balanced equation for this reaction.

(2) ..............................................................................................................................................

(b) Zinc is reacted with copper sulfate solution. The equation for the reaction is Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)

(i) What type of reaction is this? (1)

Put a cross ( ) in the box next to your answer.

A decomposition

B displacement

C dissolving

D neutralisation (ii) This reaction is exothermic. On the diagram below draw labelled lines to show the relative energies of the reactants and products in this reaction.

(2)

75

4 The gases nitrogen and hydrogen react to form ammonia, as shown in the balanced equation below. The ⇌ sign

shows that this reaction is reversible. In industry the reaction is often carried out in the presence of small pieces of

iron, which act as a catalyst. A catalyst does not alter the products formed in the reaction.

N2(g) + 3H2(g) ⇌ 2NH3(g)

a State the role of a catalyst in a reaction.

_______________________________________________________________________________ (1)

b State why the iron catalyst is in the form of small pieces rather than large lumps.

________________________________________________________________________________ (1)

c This reaction profile represents the energy changes

that occur during the reaction of nitrogen and

hydrogen without a catalyst present.

i On the figure, draw in a dotted line to represent

the reaction profile when a catalyst is used.

(2)

ii Draw an arrow on the figure to show the

activation energy for the reaction without the

catalyst.

(1)

5 The energies of some common bonds are shown in the table below.

Covalent bond C H O H O = O C = O C C C = C

Bond energy (kJ mol−1)

414 458 497 798 346 602

a State what is meant by the energy of a bond.

________________________________________________________________________________ (1)

b Use the bond energies in the table to calculate the energy change (in kJ mol−1) that occurs when ethene is

burned completely in oxygen. The equation for the reaction is shown below.

Answer: ______________________ kJ mol−(3)

76

C2 Key Assessment Task Rates of Reaction (H)

Reactions can occur when particles collide. Rates of reactions can be altered by changing conditions. Explain how the rate of reaction between a solid and a liquid is altered by changing the size of the pieces of solid and by changing the temperature of the liquid. (6)

…….…...............................................................................................................................................................................................................................

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Rates of Reaction (F)

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…….…...............................................................................................................................................................................................................................

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Hydrochloric acid reacts with magnesium metal to produce hydrogen gas.

magnesium + hydrochloric acid → magnesium chloride + hydrogen

Describe how you could use magnesium ribbon and a solution of hydrochloric acid to show

that decreasing the concentration of the hydrochloric acid changes the rate of this reaction.

77

RATES OF REACTION AND ENERGY QUESTIONS Q1. A student used the equipment in Figure 6 to investigate the rate of reaction between zinc and excess dilute hydrochloric acid.

Figure 6

The student uses the following method:

place a known mass of granulated zinc into the conical flask

pour 25 cm3 of dilute hydrochloric acid (an excess) into the conical flask and fit the bung quickly into the neck of the flask

measure the volume of gas produced every 20 seconds until after the reaction finishes.

Figure 7 shows the results.

(a) Give the name of a piece of equipment that can be used to measure 25 cm3 of dilute hydrochloric acid accurately.

___________________________________________________________________________________________(1)

78

(b) Draw a graph of the volume of hydrogen gas produced against time using the grid. (3)

(c) The average rate of reaction in the first 20 seconds in cm3 of hydrogen produced per second is (1)

A 2.1

B 8.4

C 21

D 84

(d) The student repeated the experiment keeping all conditions the same but using the same mass of powdered zinc instead of granulated zinc.

On the grid above sketch the graph you would expect when the experiment is repeated using powdered zinc. Label your line A (2)

Q2. During any reaction, reactants are used up and the rate of reaction decreases.

Explain, in terms of particles, why the rate of reaction decreases .(2)

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Q3. The decomposition of hydrogen peroxide is catalysed by adding a small amount of manganese(IV) oxide.

Which of these graphs shows the mass of the catalyst as the reaction takes place? (1)

Q4. What type of chemical change causes a decrease in temperature? (1)

A combustion

B endothermic

C exothermic

D neutralisation Q5. The energies of some bonds are shown in the table.

Hydrogen reacts with chlorine to form hydrogen chloride.

H2(g) + Cl2(g) → 2HCl(g)

Calculate the energy change, in kJ mol–1, for the reaction of 1 mol of hydrogen gas, H2, with 1 mol of chlorine gas, Cl2, to form 2 mol of hydrogen chloride gas, HCl.

(4)

energy change = ........................................................... kJ mol−1

80

Q6. When solid ammonium chloride is shaken with water, a colourless solution forms and the temperature changes from 20°C to 16°C.

Give the name of the type of heat change occurring.

(1)

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Bond C-C C-H C=O C-O O-H O=O

Bond energy

kJmol-1

346 413 740 360 463 497

Q7. Use the bond energies in the table above to calculate the overall energy change of the reaction below.

CH4 + 2O2 CO2 + 2H2O

Q8. Use the bond energies in the table above to calculate the overall energy change of the reaction below.

C2H5OH + 3O2 2 CO2 + 3H2O

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CORE PRACTICAL – RATES OF REACTION (TEMPERATURE)

Section Answer

What is practical about?

What was changed ?

What was measured?

How was it measured?

What was kept the

same?

What equipment was

used to make the

measurements

82

CORE PRACTICAL – RATES OF REACTION (SURFACE AREA)

What is the practical about?

What was changed?

What was measured?

What was kept the same?

What could you use to measure the gas volume more accurately?

If 65cm3 of gas was produced in 75s calculate the average rate of volume of gas produced per second.

83

FUELS AND EARTH SCIENCE

Describe a hydrocarbon

Describe crude oil

Describe how crude oil is separated

Give the names and use of the different fractions

Gases –

Petrol –

Kerosene –

Diesel Oil-

Fuel Oil-

Bitumen-

Give the rhyme to remember the order of the fractions from fractional distillation

Describe how the number of carbon and hydrogen atoms in the molecule changes the

Boiling point-

Viscosity –

Ease of ignition-

Describe an homologous series

What is produced in the complete combustion of a hydrocarbon?

What is produced in the incomplete combustion of a hydrocarbon?

Explain how carbon monoxide behaves as a toxic gas

How does sulphur dioxide get produced from hydrocarbon fuels?

84

How is acid rain caused?

How do oxides of nitrogen get produced?

Give the advantages and disadvantages of using hydrogen rather than petrol as a fuel

Where is methane found?

What does cracking do?

Why is cracking necessary?

How were the gases produced in the Earth’s early atmosphere?

What were the gases in the Earth’s early atmosphere?

How did the oceans form?

Describe 2 ways in which the amount of carbon dioxide in the Early atmosphere

decreased

Describe the chemical test for oxygen

Describe the greenhouse effect and explain how it occurs

What is the evidence for human activity causing climate change?

Describe the potential effects on the climate of increased levels of carbon dioxide and

methane

85

QUESTION PRACTICE

1.The modern atmosphere is a mixture of oxygen and other gases.

Which of these is the chemical test for oxygen? Tick one box.

A Limewater turns milky.

B A lighted splint gives a pop.

C A glowing splint relights.

D Damp red litmus paper turns blue. (1)

2. The use of hydrocarbon fuels can cause the production of sulfur dioxide and oxides of nitrogen.

Explain how this sulfur dioxide forms.

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________________________________________________________________________________ (2)

3. Explain how these oxides of nitrogen are produced.

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4. At oil refineries, some crude oil fractions undergo a process called cracking.

Give two reasons why cracking is needed.

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5. Propane is a substance found in crude oil. Its molecular formula is C3H8.

Draw the structure of propane, showing all the covalent bonds.

(1)

Propane is a member of the alkane homologous series of compounds. The next member of this

homologous series is called butane.

Write the molecular formula of butane.

_____________________________________________________________________________ (1)

Explain why the alkanes form a homologous series.

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Incomplete combustion of propane happens in a limited supply of air. Carbon monoxide forms.

i Explain how carbon monoxide behaves as a toxic gas.

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ii Balance this equation for the incomplete combustion of propane.

C3H8 + ___ O2 → C + ___ CO + ___ H2O (1)

iii Write a balanced equation for the complete combustion of propane.

_____________________________________________________________________________ (2)

An international body called the IPCC (Intergovernmental Panel on Climate Change) was set up in 1988.

It is responsible for assessing the science related to climate change. The IPCC publishes reports every few years.

The image shows part of a newspaper article following the third IPCC report.

e Describe how greenhouse gases in the atmosphere keep the Earth warm.

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2. Explain whether the graph provides evidence that an increase in carbon dioxide is causing the Earth’s

temperature to rise.

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f Explain how climate change could lead to increasing sea levels.

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Describe two different ways in which the effects of rising sea levels could be limited.

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________________________________________________________________________________ (2)

6. Crude oil is a complex mixture of hydrocarbons. These hydrocarbons are separated into useful mixtures,

called fractions. Explain how crude oil is separated into fractions.

Name two liquid crude oil fractions and explain how their properties differ, making them suitable for

different uses.

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