Answer all questions

1. The diagram represents the structure of an atom of isotope A of an element.

(a) (i) Name the particles X, Y and Z.

X .....................................................................................................................................................

Y .....................................................................................................................................................

Z ................................................................................................................................................(3)

(ii) Which of the particles X, Y and Z have approximately the same mass?

...................................................................................................................................................(1)

(iii) Give the atomic number and mass number of this atom.

Atomic number

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

Mass number

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

(b) (i) This element has another isotope, B, with a mass number one less than isotope A.

State the composition of the nucleus of an atom of isotope B.

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

(ii) Why do these isotopes have the same chemical properties?

....................................................................................................................................................(1)

(Total 9 marks)

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2.Magnesium is a metal that is used in alloys.

(a) What do you mean by an alloy?

......................................................................................................................................... (1)

(b) Magnesium has an atomic number of 12 and several stable isotopes.

The table shows the numbers of protons, neutrons and electrons in particles P, Q, R, S, T

and U.

Which of these particles are atoms which are magnesium isotopes? (indicate your answer with

a X in a box.

A P, Q and T

B P, Q, S and U

C P, S and U

D P, R and S (1)

(b) Explain how the particles are arranged in the structure of magnesium metal

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

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

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

(Total 4 marks)

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3. The noble gases are in group 0 of the periodic table.

(a) Argon is the most abundant noble gas.

It has been used for many years in light bulbs.

(i) The atomic number of argon is 18.

Give the electronic structure of an argon atom.

.................................................................................................................................................(1)

(ii) State and explain, in terms of the electronic structure, why argon is used in

light bulbs.

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

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

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

(b) Neon exists as two isotopes.

Calculate the relative atomic mass of neon to 3 significant figures.

Answer = ................................................. (2) (Total 5 marks)

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4. (a) Five experiments were set up to investigate the effect of air, water and other metals on

the rate of rusting of an iron nail. The experiments were left for several days.

Experiment A: a nail was put in a test tube, covered with water and left exposed to

the atmosphere.

Experiment B: a nail was put in a test tube, covered with water that had been

previously boiled and a layer of oil was poured on top of the water.

Experiment C: a nail was put in a test tube that contained anhydrous calcium chloride

and the top was sealed with a bung.

Experiment D: a nail wrapped with a tin strip was put in a test tube, and left exposed to the

atmosphere.

Experiment E: a nail wrapped with a magnesium strip was put in a test tube, and left exposed

to the atmosphere.

(i) State in which experiment(s) you would expect rusting to occur.

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

(ii) In Experiment B, explain why the water was boiled and then covered in a layer

of oil.

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

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

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

(iii) In Experiment C, state the purpose of the anhydrous calcium chloride.

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

....................................................................................................................................................(1)

(iv) What do you expect to see in experiment D and experiment E?

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

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

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(v) Give reasons for your expected observations in experiment D?

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

....................................................................................................................................................(1)

(b) (i) Explain why a block of zinc attached to the steel hull of a ship slows down the

rusting process.

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

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

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

(Total 10 marks)

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5. This question is about the reactions of the metals calcium, iron and zinc.

(a) Samples of each of the powdered metals were placed in separate beakers of water.

Only calcium reacted immediately.

Describe two observations that could be made during the reaction of calcium with

water. Write a chemical equation for the reaction.

Observation 1 ................................................................................................................................

Observation 2 ................................................................................................................................

Equation ....................................................................................................................................(3)

(b) A reaction occurred when powdered zinc was heated in steam.

Name the zinc compound formed. Write a chemical equation (word/formula) for the reaction.

Name of compound .......................................................................................................................

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

(c) Some powdered zinc was added to a solution of iron (II) sulphate.

(i) Write an ionic equation to show the reaction that occurs.

...................................................................................................................................................(1)

(ii) State the type of reaction occurring.

...................................................................................................................................................(1)

(e) Galvanizing is one method used to prevent iron from rusting.

(i) A sheet of galvanized iron was scratched and left in the rain. The exposed iron

did not rust. Explain why.

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

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

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

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

(Total 9 marks)

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6. Bromine is an element in Group VII of the Periodic Table.

(a) Complete the diagram below to show the arrangement of the molecules in liquidbromine.

(2)

(b) A teacher placed a small amount of liquid bromine in the bottom of a sealed gas jar of

air. After two minutes brown fumes were seen just above the liquid surface. After one

hour the brown colour had spread completely throughout the gas jar.

Use the kinetic particle theory to explain these observations.

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

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

....................................................................................................................................................(3)

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(d) Magnesium salts are colourless but Group VII elements are coloured.An aqueous solution of magnesium bromide reacts with an aqueous solution ofchlorine.magnesium bromide + chlorine magnesium chloride + bromine

State the colour change in this reaction.

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

(e) A solution of magnesium bromide will not react with iodine.

Explain why there is no reaction.

.................................................................................................................................................. (1)

(f) The structures of some compounds containing bromine are shown below.

(i) Write the simplest formula for the substance with structure A.

................................................................................................................................................... (1)

(ii) State the name of the substance with structure D.

.................................................................................................................................................. (1)

(iii) State the type of bonding within a molecule of structure C.

.................................................................................................................................................. (1)

(iv) Which two structures are giant structures?

.................................................................................................................................................. (1)

(v) Why does structure A conduct electricity when it is molten?

.................................................................................................................................................. (1)

(Total 13 marks)

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7. A student separated two alkanes, hexane (bp 69 °C) and heptane (bp 98 °C), using theapparatus shown below.

(a) (i) Name the piece of apparatus labeled M.

................................................................................................................................................... (1)

(ii) What is it used for?

................................................................................................................................................... (1)

(iii) Name the piece of apparatus labeled N.

................................................................................................................................................... (1)

(iv) What is it used for?

................................................................................................................................................... (1)

(b) Why was a hot water bath used rather than a flame for heating the mixture?

................................................................................................................................................... (1)

(c) What was the reading on the thermometer when the first few drops of distillate appeared in

the beaker?

................................................................................................................................................... (1)

(d) How did the student know when all the first alkane had distilled over?

....................................................................................................................................................(1)

(Total 7 marks)

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8. (a) Calculate the empirical formula of the oxide of phosphorus that has the following

composition by mass.

P = 56.4% O = 43.6%

(3)(b) Phosphene, PH3, is a covalent compound.

(i) Give a reason why the bond between phosphorus and hydrogen is covalent.

................................................................................................................................................... (1)

(ii) Draw a diagram to show the outer shell arrangement of electrons in

Phosphene

(3)

(c) Sodium chloride is an ionic compound.

(i) Show the formation of this compound using a dot cross diagram,.

(2)

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(ii) Explain what an ionic bond is.

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

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

(Total 11 marks)

9. Identify, by name or formula, each of the substances labelled A to H.

(a) A green powder A was heated and it turned into a black solid B and a colourless

gas C that extinguished a burning splint.

A .....................................................................................................................................................

B .....................................................................................................................................................

C ............................................................................................................................................... (3)

(b) When a large piece of a silvery metal D was dropped onto water, it reacted vigorously a

yellow flame was seen. A colourless gas E and an alkaline solution F were produced.

D .....................................................................................................................................................

E .....................................................................................................................................................

F ............................................................................................................................................... (3)

(c) When an aqueous solution of silver nitrate followed by few drops of nitric acid were added

to a colouress solution G, a yellow precipitate H was formed and a solution of potassium

nitrate remained.

G ....................................................................................................................................................

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

(Total 8 marks)

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10. Electrolysis is the decomposition of a liquid by the passage of an electrical current.

(a) Aqueous copper(II) sulphate contains the following ions, Cu2+, H+, OH– and

(SO4) 2–.

Aqueous copper(II) sulphate can be electrolysed using inert electrodes.

The electrode reactions are represented below.

Cathode Cu2+ + 2e– → Cu

anode 4OH– → O2 + 2H2O + 4e–

(i) Explain why copper, not hydrogen, is formed at the cathode.

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

................................................................................................................................................... (1)

(ii) Explain why the formation of oxygen at the anode is an example of oxidation.

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

................................................................................................................................................... (1)

(b) Molten lead(II) bromide decomposes when an electric current is passed through it.

(i) Explain why solid lead(II) bromide will not conduct electricity but molten

lead(II) bromide will.

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

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

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

(ii) Construct the equations for the two electrode reactions.

cathode ...........................................................................................................................................

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

(Total 6 marks)

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11. This question is about chlorine and other elements in Group 7 of the Periodic Table.

(a) Complete the table to show the colours and states of some elements in Group 7.

Name of element Colour State at room temperaturechlorine green gas

bromine brown

iodine Solid

(2)(b) The diagram shows the electrolysis of an aqueous solution of a compound.

The electrolysis produces chlorine and another gas.

(i) Add a label to the diagram to show the chlorine gas. (1)

(ii) Identify the other gas produced during the electrolysis.

................................................................................................................................................... (1) (c) When chlorine gas is bubbled into colourless sodium bromide solution a reaction

takes place. The solution becomes brown.

(i) Write a word equation for the reaction which takes place.

....................................................................................................................................................(1)

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(ii) What name is given to this type of reaction?

....................................................................................................................................................(1)

(iii) What does this reaction indicate about the reactivity of chlorine compared to

bromine?

....................................................................................................................................................(1) (Total 7 marks)

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12. (a) A student was asked to draw a diagram to show apparatus he would use to prepare

carbon dioxide gas in the laboratory. This is part of the diagram he drew.

(i) Complete the diagram by labeling and drawing a suitable method of collecting the gas. (3)

(ii) Write a chemical equation, including state symbols, for the reaction that occurs

in the conical flask.

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

....................................................................................................................................................(3)

(b) A teacher prepares a gas jar of oxygen.

She then lights a piece of magnesium ribbon and places it in the gas jar.

A vigorous reaction occurs.

Give two observations she could make during the reaction between magnesium and

oxygen.

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

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

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(c) The ionic compound formed during the reaction in the gas jar is magnesium oxide.

The melting point of magnesium oxide is 2857 °C.

The melting point of sodium chloride is 801 °C.

(i) Explain why both magnesium oxide and sodium chloride have high melting

points.

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

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

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

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

(ii) Explain why the melting point of magnesium oxide is much higher than that of

sodium chloride.

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

................................................................................................................................................... (1)

(Total 11 marks)

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1.atomic structure 92 isotopes 43 rmm 54 rusting 115 reactivity series & rusting 96 gp 7 & structure if compounds 147 separation technique 78 covalent & ionic compounds 79 chemical identification 810 elecrolysis cuso4 & PbBr2 611 Gp 7 & elecrolysis aq NaOH 912 Preparation of CO2 & reaction of Mg & O2 12

2.

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