- 1 -

IAL CHEMISTRY

Unit 1

Revision Booklet

By Md. Kamrul Alam Khan

- 2 -

Atomic Structure: The atom is composed of the following sub-atomic particles. Complete the table with their following properties.

Name Relative Mass Relative Charge

Proton

-1

Neutron

In an electric field both protons and ________ would be deflected but _________ would not be.

The Atomic Mass is defined as the number of _______ in the nucleus. In an atom this is also the number of ________.

- 3 -

Atomic Mass: Complete the following definitions. Relative Atomic Mass (Ar): the _______ mass of 1 ______ of atoms relative to 1/12 the mass of 1 mole of ___________. Relative Isotopic Mass: the mass of 1 _____ of an _______ relative to 1/12 the mass of the mass of 1 mole of ___________. Relative Molecular Mass (RMM): the _______ mass of 1 mole of compound relative to 1/12 the mass the mass of 1 mole of ___________. It is the sum of all the Relative ______ masses of its constituent ______. Molar Mass: is the ______ of one mole of the substance (gmol-1) The number of neutrons in an atom is:

No. of Neutrons = Mass Number – Atomic Number

- 4 -

Complete the following table: Protons Neutrons Electrons Atomic

Number Atomic Mass

Symbol

A

7 14

B

16 15

C

10 8 16

D

35 36 79

E

30

F

27Al3+

- 5 -

Isotopes are atoms of the same ______ which have the same number of ______ but different number of ______. The Relative ______ Mass must be calculated from the _________ and Relative Isotopic Mass of every isotope. RAM = Sum of (Isotopic Mass x % Abundance)

100

Qu 1) For Boron there are two isotopes with their abundances in the brackets. Calculate the Relative Atomic Mass. 10.0 (18.7%) 11.0 (81.3%)

10.8

- 6 -

Mass Spectrometer: The mass spectrometer measures the relative abundance and relative mass of a sample. 1)A ________ sample is first bombarded with _______, from a heated _______, to form positive ions. The very fast ________ strike the sample removing an electron.

X(g) X+(g) + e-

Na(g) Na+(g) + e-

Br2(g) Br2+(g) + e-

2)These _______ ions are accelerated by a ________ plate and form a beam. 3)The beam is then deflected by a ________ field and recorded. 4)The magnetic field strength is _______ to record all possible masses and their relative abundances. The spectra can be used to calculate both the Relative Atomic Mass and the Relative Molecular Mass.

- 7 -

Qu 2) Calculate the Relative Atomic Mass of Neon from the following spectra.

- 8 -

Electron Configuration: Successive ___________ Energies provide evidence for the existence of quantum shells. i.e. that ________ exist in energy levels with distinct energy. The variation in 1st Ionisation Energies provide evidence for the existence of characteristic energy levels consisting of s, p and d orbitals. An orbital is an area in which there is a high probability of locating an electron. Each orbital can hold a maximum of _____ electrons. Below draw diagrams to represent the shapes of: a) an s orbital b) a p orbital

- 9 -

Energy Level s p d Total electrons 1 1 2 2 1 3 8 3 1 3 5 18 4 1 3 8

The order of filling orbitals is in order of energy. 1s 2s 2p 3s 3p 4s 3d 4p e.g. Calcium (20 electrons)

1s2 2s2 2p6 3s2 3p6 4s2 Complete the following:

1) Potassium 2) Carbon 3) Iron (NB 3d is written before 4s)

- 10 -

The electronic configurations of Chromium and Copper are unique because the 3d and 4s orbitals are so close in ______ it is possible to promote an electron to achieve a more ______ configuration. A half-full or full d orbital is much more stable.

Cr 1s2 2s2 2p6 3s2 3p6 3d5 4s1 Cu 1s2 2s2 2p6 3s2 3p6 3d10 4s1 The electronic configurations can also be

expressed using the electrons-in-boxes notation. Complete the following table to show the electronic configuration of Nitrogen (NB electrons are unpaired where possible).

Orbital 1s 2s 2px 2py 2pz

N The Periodic Table has three main areas

depending upon the energy sub-level in which the outer electron is situated.

- 11 -

The chemical properties of an element are governed by the ________ configuration and in particular the number of outer electrons. Those elements with similar __________ (i.e. in the same group of the Periodic Table) will form compounds with similar _______.

Transition metals first lose the ___ electrons before the ___ electrons. Because of the close proximity in energy of the energy levels it is possible for the transition metals to form a number of different ions (i.e. they can have ions with more than one valency).

- 12 -

Atomic Mass: Complete the following definitions. Relative Atomic Mass (Ar): the _______ mass of 1 ______ of atoms relative to 1/12 the mass of 1 mole carbon-12 _____. Relative Isotopic Mass: the mass of 1 _____ of an _______ relative to 1/12 the mass of 1 mole carbon-12 atom. Relative Molecular Mass (Mr): the _______ mass of 1 mole of compound relative to 1/12 the mass of 1 mole of _______-12 atoms. It is the sum of all the Relative ______ Masses of its constituent ______. The term Relative Formula Mass (Mr) is used for Ionic Compounds. Molar Mass: is the ______ of one mole of the substance (gmol-1)

- 13 -

The Mole: This is the number of particles in 12g of Carbon-12. (Avogadro’s number) The number of particles is _________ and is called _________ Number. The number of particles in any given substance can be calculated by: No of Particles = No. of Moles x _________ Number Calculate the number of particles in the following:

1) 0.5 moles of magnesium

2) 0.1 moles of sulphur

3) 0.125 moles of oxygen

- 14 -

Empirical and Molecular Formulae: The Empirical Formula is the ________ ratio of elements in a compound: The Molecular Formula is the ________ ratio of elements in a compound: e.g. Benzene:

Molecular Formulae: C6H6 Empirical Formulae: CH

To calculate the Empirical Formula you either need the ________ reacted or the ___________ masses.

- 15 -

Follow the same steps every time to calculate the empirical formula. 1 Write down the mass of each element. 2 Divide the mass by the relative atomic mass of the

element. 3 Divide numbers by the smallest number to get the

ratio of elements. 4 These numbers give the empirical formula. A compound has 24 g of carbon and 64 g of oxygen. What is its empirical formula?

Element Symbol

Mass of element

Mass ÷ Relative Atomic Mass

Divide by the smaller number

Ratio

C

24

÷ 12

2

÷ 2

1

O

64

÷ 16

4

÷ 2

2

The empirical formula of this compound is CO2.

- 16 -

1. A compound is made from 72 g of carbon and 12 g of hydrogen. Work out its empirical formula.

2. A common salt is analysed and is found to have 52.9 g of sodium and 81.7 g of chlorine. What is its empirical formula?

- 17 -

3. Aluminium ore may consist of 156 g of aluminium and 278 g of oxygen. Is its empirical formula AlO2 or AlO3?

4. A commercial paint thinner has the following composition: carbon 25.2 g; hydrogen 8.5 g; oxygen 33.7 g. What is its empirical formula?

- 18 -

Molecular Formulae: Once you have found the Empirical Forumla e.g CH2 then you can find the Molecular Formula using the Mr of the compound. Er is like Mr but for the Empirical Formula Mr / Er – this should be a whole number Molecular Formula = Mr / Er x Empirical Formula e.g. 42/14 x CH2 = C3H6 1. a) Calculate the empirical formula of the compound found to contain 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. b) Find its molecular formula given that its Mr is 180.

- 19 -

2. a) Work out the molecular formula of the following compounds given the information below?

i) empirical formula = P2O5 Mr = 284 ii) empirical formula = CH2 Mr = 56

- 20 -

Writing equations:

It is important when writing equations to do it methodically:

1. Write a word equation 2. Write the formulas for each of the species. 3. Balance the equation.

A full equation shows the full formulae of the species involved. An ionic equation shows only those ions/molecules that change in the reaction.

Write full equations for the following reactions:

a) sodium + oxygen → sodium oxide

b) aluminium + chlorine → aluminium chloride Write an ionic equation for the following reaction

c) calcium + hydrochloric acid → calcium chloride + hydrogen

- 21 -

Concentration, Volume and Moles: In solutions the number of moles is often quoted as the concentration either in mol/dm3 or M.

Number of moles = Concentration x Volume

n = c x v NB Volume is often quoted in cm3 and must first be changed into dm3 by dividing by 1000.

Calculate the following:

a) Number of moles in 2 dm3 of 0.05 mol dm-3 HCl

b) Concentration in 0.400 moles of HCl in 2.00 litres of solution

c) Volume of 0.00500 moles of NaOH from 0.100 mol dm-3 solution.

- 22 -

Reacting Masses Calculations: In order to calculate the mass of a reactant needed or product formed, volumes of products or perhaps a titration calculation you might need more than one step. The MRA approach:

1. Moles: Calculate the initial number of moles of one of the species using either: n=m/Mr (solids) n=c x v (solutions) Pv = nRT (gases)

2. Ratio: Calculate the number of moles of the other species using the ratio from the equation:

3. Answer: Calculate your answer now that you have the number of moles of the species required.

- 23 -

The reaction below is known as the Thermitt reaction, which is used to form molten iron to mould train tracks together. What mass of aluminium powder is needed to react with 8.00 g of iron (III) oxide?

2Al + Fe2O3 → Al2O3 + 2Fe

25.0 cm3 of 0.0400 mol dm-3 sodium hydroxide solution reacted with 20.75 cm3 of sulphuric acid in a titration. Find the concentration of the sulphuric acid.

- 24 -

Percentage Yield:

% yield = mass of product obtained x 100 ______________________________________________________________

maximum theoretical mass of product The theoretical maximum mass of product must first be calculated using the reacting masses method: Titanium can be extracted from titanium chloride by the following reaction. TiCl4 + 2 Mg → Ti + 2 MgCl2 a) Calculate the maximum theoretical mass of titanium that can

be extracted from 100 g of titanium chloride . b) In the reaction, only 20 g of titanium was made. Calculate the percentage yield.

- 25 -

Pecrentage Atom Economy:

% atom economy = mass of desired product x100 _____________________________________________

total mass of reactants 1) Calculate the atom economy to make sodium from sodium chloride. 2NaCl → 2 Na + Cl2 2) Calculate the atom economy to make hydrogen from the reaction of zinc with hydrochloric acid. Zn + 2 HCl → ZnCl2 + H2

3) Calculate the atom economy to make iron from iron oxide in the Blast Furnace. Fe2O3 + 3CO → 2Fe + 3CO2

- 26 -

Types of Bond:

1) Ionic This is the _________ attraction between oppositely charged ions. Cation:- ________ ion due to the loss of electrons Anion:- _______ ion due to the gain of electrons

2) Covalent This is the _______ of a pair of electrons in which both species donate ____ electron.

3) Dative Covalent This is the ______ of a pair of electrons in which _____ electrons come from the same species

4) Metallic Bond The attraction between _______ ions and the sea of _________ electrons.

- 27 -

Ions:

i) Cations have a radius ______ than their atomic radius. The greater the number of electrons _____ the smaller the radius.

ii) Anions have a radius ______ than their atomic radius. The ionic radius increases down the group.

iii) Cations with a _____ radius and/or _____ charge have a ______ charge density, and so are very ________. Anions with a ________ radius are very polarisable. If either the cation is very polarising or the anion is very polarisable, the outer ________ in the anion will be pulled towards the ______ and the bond will have some ______ character.

- 28 -

Electronegativity:

i) The electronegativity of an element is a measure of the attraction its atoms has for a pair of ________ in a covalent bond. Metals usually have _____ electronegativities. Non-metals have _____ electronegativities. If there is a very ______ difference in electronegativity then the bond will be more _____ than covalent but all ionic bonds show some _______ character. If a covalent bond is formed between two different elements then there will be an _______ sharing of the electrons. Therefore a _____ bond is formed.

However due to the _______ of some molecules they do not have a ________ dipole because the polar bonds cancel. e.g.

No overall dipole.

- 29 -

There are various types of intermolecular bond that occur because of the attraction between dipoles.

i) Van der Waals: This _____ attraction occurs between an ________ dipole in one molecule and an ______ dipole in an adjacent molecule.

ii) Permanent Dipole: This attraction occurs

between two molecules that have a permanent dipole. Are _______ than Van der Waals for molecules with similar mass.

iii) Hydrogen Bond: This is a fairly ______

interaction that occurs between two molecules that have a permanent ______ involving ________ (non-metal with the lowest electronegativity)

- 30 -

Properties:

The properties of a substance depend upon the structure and bonding of a substance.

a) Ionic: 1. Have a very regular three-

dimensional arrangement of ions (ionic _______). The crystals are very _______.

2. Have very high _______ points due to the strong attraction.

3. Conduct electricity when ______ or in aqueous solution because they have free moving _____.

4. Most ionic solids are water-soluble because the ______ required to separate the ______ is compensated for by the exothermic nature of hydration. The strong ionic bonds are replaced by _________ to the polar water molecules.

- 31 -

b) Covalent:

Covalent compounds vary and can be separated into four distinct groups:

i) giant atomic e.g. diamond, graphite, quartz (SiO2)

a. Have very high _______ points because they have a ______ number of covalent bonds and this requires a lot of ______ to break them.

b. Diamond and quartz are ______ structures due to the ________ of the covalent bond.

c. Graphite can _____ electricity due to the presence of delocalised _______.

d. Graphite is a good _______ because the layers can easily slide over each other.

- 32 -

ii) simple molecular e.g. I2 and many other organic substance.

a. Usually have ___ boiling points due to the ______ of the Van der Waals forces.

b. As the molecule increases in ____ the Van der Waals forces become ______.

c. Iodine is a solid at room temperature but ______ when heated as little energy is needed to overcome the forces.

d. Do not conduct _______ because the ________ are tightly held in the covalent bond.

e. Do not _______ in polar substances because their molecules are not attracted to the polar molecules.

- 33 -

iii) hydrogen-bonded molecular e.g. Ice and ethanol

a. Have unusually high ________ points because of the fairly strong _________ Bond between molecules.

b. Can _______ in polar solvents because of the attraction between molecules.

c. Ice has a ______ density than water because the ________ bonds in solid ice, which hold the molecules together, are in _______ positions and lead to an open structure. In water the hydrogen bonds are constantly being ______ and made.

- 34 -

iv) non-crystalline e.g. polymers like polyethene.

a. Are generally ________ with high melting points because of the strong Van der Waals forces between the molecules.

b. Some polymers form cross-links between the strands and therefore cannot be _________.

- 35 -

Melting Point: When a solid is heated from room temperature

until ______. The particles (ions, molecules or atoms)

_______ more. As the temperature rises the vibrations

________ until they become so great that the _______ between the particles are overcome, and the regular arrangement in the lattice breaks up.

The substance is then a ______.

The ________ the forces between the particles

the ________ the amount of energy required and therefore the _______ the melting point.

- 36 -

Boiling Point Trends:

i) Noble Gases: The boiling point ________ down the group. As the number of electrons ________ the Van der Waals forces increase in _______ therefore more energy is required.

ii) Group 5,6and 7 Hydrides:

The first member of the series has a higher than usual _______ point due to the presence of _________ bonding. After the drop to the second member there is a steady _______ as the number of _______ increases and so therefore does the _______ of the Van der Waals force.

- 37 -

Molecular Shapes: These are explained by the Valence Shell Electron Pair Repulsion Theory:

i) The _______ pairs arrange themselves as far apart from each other as possible in order to _______ the repulsion.

ii) The repulsion between ____ pairs is greater than that between a lone pair and a _____ pair, which is greater than that between two _____ pairs.

lp-lp > lp-bp > bp-bp

iii) The number of bond pairs of electrons and lone pairs in the molecule should be counted.

iv) Any bond pairs should be ignored when working out the shape of a molecule.

- 38 -

The structures are based upon the following.

2 Bond pairs

Linear Bond Angle 180

3 bond pairs

Triangular Planar

Bond Angle 120

4 Bond Pairs

Tetrahedral Bond Angle 109.5

- 39 -

5 Bond Pairs Trigonal

Bipyramidal Bond Angle 90 and 120

6 Bond Pairs

Octahedral Bond Angle 90

- 40 -

However the shape will differ if any of the pairs are lone pairs because of the greater repulsion. e.g. Ammonia (Bond Angle 107)

Pyramidal

Water (Bond Angle 104.5) Non-linear

- 41 -

You should be able to draw shapes of the following:

i) HCl (Linear)

ii) CO2 (Linear)

iii) SO2 (Trigonal Planar)

- 42 -

iv) SO32- (pyramidal)

v) CO32- (trigonal planar)

vi) NO3- (trigonal planar)

vii) NH4+ (tetrahedral)

- 43 -

Metallic Bonding:

The metallic bond is the _________ between the regularly arranged positive _______ and the sea of _________ electrons.

Metals are very good __________ of electricity because of the mobility of their delocalised ________.

Metals have _____ melting points and boiling points due to the _____ attraction. The greater the ______ on the cation the ______ the metallic bond and therefore the _______ the melting point.

- 44 -

Periodicity: Elements are classified as s, p or d depending upon their position in the Periodic table. Atomic Radius: Across the Period from Na – Ar the atomic radius ________. This is because as the _________ charge increases the electrons are all in the same ________ level. Therefore the electrons have the same _____________ and so the attraction to the outer electrons is stronger. This means the radius of the atom will be _____________.

- 45 -

Melting Point: As we go across the period the melting point initially ________. This is because the metal ions have greater __________ and therefore the attraction to the sea of delocalised electrons is __________. In group 4 Silicon is _______________ and therefore has a very high melting point. In groups 5,6, and 7 the elements are ___________ with small ______________ (P4, S8 and Cl2). They have _____ intermolecular forces and therefore _____ melting points. Argon is a ___________ element and therefore has very weak ______________ forces between its atoms.

- 46 -

Ionisation Energies: First Ionisation Energy: The _______ change when 1 m____ of electrons is removed from 1 m_____ of atoms in the ________state. X(g) → X+(g) + e-

Second Ionisation Energy: The _______ change when 1 m____ of electrons is removed from 1 m_____ of singly charged p________ ions in the ________state. X+(g) → X2+(g) + e- Qu 3) Write an equation to show the following:

a) 1st I.E. of Mg

b) 2nd I.E. of Mg

- 47 -

Trends:

1) Across a Period the Ionisation Energy ________ as the nuclear charge ________. The electrons are in the same energy _____ and therefore the _________ to the outer electron is _______ and more energy is required to remove it.

2) Down a group the Ionisation Energy _______

as the outer electron is _______ from the nucleus. Although there is a greater nuclear ______ the inner electron shells _______ the valency electron and therefore the attraction is _______ and less _______ is required to remove it.

3) Successive Ionisation Energies are always

greater than the previous as there are fewer ________ and therefore greater ________. A very large jump in the value indicates the electron is being removed from an ______ shell.

- 48 -

Exceptions to the general rule are: Al < Mg This is because the electron is removed from a _______ energy sub-level. The full s-orbital _______ the outer electron and therefore the _________ is weaker. N < O This is because the ________ between the paired electrons in a p-orbital makes it _______ to remove one of them.

- 49 -

Introduction to Organic Chemistry: Empirical Formula: the s_________ ratio of elements in

a molecule.

e.g C2H4 → CH2 Molecular Formula: the a_______ number of atoms of

each element in a molecule. Structural Formula: This shows the unique arrangement

of atoms in a molecule without showing all the bonds.

e.g CH3CH2CH3

Displayed Formula: This shows every atom and every

bond in the molecule. e.g.

- 50 -

Homologous Series: A family or organic compounds, with the same f________ group, but different c_______ chain length.

Functional Group: A r________ group within a molecule. Structural Isomerism: Molecules that have the same

m_______ formula but different s_______ formula. The can be positional isomers, functional group isomers or chain isomers.

a) Draw the structural formula of pentane.

b) Draw the displayed formula of methylpropane.

c) To which homologous series does Butene belong?

- 51 -

d) Give an example of two positional isomers of chloropropane.

e) Give two examples of functional group isomers of C5H10

f) Give two chain isomers of C4H10

- 52 -

Naming compounds: The main part of the name is defined by the number of carbon atoms in the longest possible chain Generally functional groups are given suffixes (-ane, -ene, -ol) except the haloalkanes which are given prefixes (chloro, bromo, iodo). Branches are also given prefixes e.g. methyl, ethyl. Name the following molecules:

- 53 -

Alkanes: Alkanes are s____________ hydrocarbons

Petroleum is a m_________ consisting mainly of alkane

hydrocarbons

Different components (fractions) of this m__________

can be drawn off at different levels in a f____________

column because of the t_____________ gradient

C____________ involves the breaking of C–C bonds in

alkanes

T_________ c_________ takes place at high

p________ and high t___________ and produces a high

percentage of a_________

C__________ cracking takes place at a slight p________,

high t___________ and in the presence of a z________

catalyst and is used mainly to produce motor fuels and

a___________ hydrocarbons

- 54 -

a) What are the economic reasons for cracking? Alkanes are used as f______s. Their combustion can be

c___________ or i_________.

b) What are the products when hydrocarbons are burned

in excess oxygen? c) What are the procuts when a hydrocarbon is burned

in a limited supply of oxygen? d) What other polluntant can be produced by the

internal combustion engine? e) What polluntant is caued by the main impurity in fossil

fuels?

- 55 -

Pollutants caused by the internal combustion engine can be

removed using c___________ c____________.

S__________ d________ can be removed from flue

gases by reacting it with C________ o_________.

f) Write a word equation for this reaction? The combustion of fossil fuels (including alkanes) results

in the release of c________ d________ into the

atmosphere

C_______ d________, m________ and water vapour are

referred to as g_________ gases and that these gases

may contribute to global _________.

- 56 -

MD. KAMRUL ALAM KHAN, B.Sc Honors in Chemistry (SUST), M.Sc in Chemistry (SUST), CCNA

(All through first class), CELL: 8801557704046