Definitions

Question 1

Relative Atomic Mass (of
an element)

Answer 1

It is the weighted average of the isotopic masses of one atom of an element relative to 1/12 the mass of one atom of carbon -12

Question 2

Relative Isotopic Mass

Answer 2

It is the mass of one atom of the isotope relative to 1/12 the mass of one atom of carbon-12

Question 3

Relative Molecular Mass

Answer 3

It is the weighted average of the isotopic masses of one atom of an element relative to 1/12 the mass of one atom of carbon -12

Question 4

Relative formula mass

Answer 4

It is the wighted average of the masses of one molecule of a substance relative to 1/12 the mass of one atom of carbon -12.

Question 5

Mole (mol)

Answer 5

The amount of substance that contains exactly 6.02 x 1023 mol^-1 particles

Question 6

Oxidation and Reduction

Answer 6

[O] loss of electrons, gain O, lose H, ON increase
[R] gain of electrons, lose O, gain H, ON decrease

Question 7

Disproportionation reaction

Answer 7

A redox reaction in which the same element in the same reactant undergoes oxidation and reduction simultaneously. The concentrations of the products and reactants remain the same in a closed system

Question 8

Avogadro’s Law

Answer 8

Equal volumes of all gases under the same conditions of temperature and
pressure contain the same number of particles

Question 9

Bronsted-Lowry Theory

Answer 9

Acid: proton donor
Base: proton acceptor

Question 10

Lewis acid-base Theory

Answer 10

Acid: electron pair acceptor
Base: electron pair donor
to form a dative bond

Question 11

Le Chatelier’s Principle

Answer 11

1. as temperature increases
2. the position of equilibrium shifts right to favour the endothermic
   reaction by absorbing the excess heat
3. partially offsetting the change

Question 12

enantiomers

Answer 12

Stereoisomers that are non-superimposable mirror images of each other. They have identical physical and chemical properties except that they rotate plane polarised light in opposite directions.

Question 13

racemic mixture

Answer 13

A mixture containing equal amounts
of each enantiomer. The mixture is optically inactive as there is no NET rotation of plane polarised light.

Question 14

ionic bonding

Answer 14

electrostatic attraction between oppositely charged ions.

Question 15

covalent bonding (and hybridisation)

Answer 15

Electrostatic attraction between shared pair of electrons and positively charged nuclei is the
covalent bond

-Expansion of Octet structure
->elements in period 3 can promote a paired 3s or 3p electron on to vacant low-lying
energetically accessable orbital 3p subshell.

Question 16

empirical formula?

Answer 16

The empirical formula of a compound is the simplest formula that shows the simplest whole number ratio of the atoms of each element present in the compound.

Question 17

molecular formula?

Answer 17

The molecular formula. of a compound shows the actual number of atoms of each element in one molecule of the compound. It is a simple multiple of the empirical formula and can only be obtained if the molar mass is known.

Question 18

Basic assumptions when doing ideal gas / kinetic theory of gas ?

Answer 18

1. A gas is composed of tiny particles that have negligible volumes compared to volume of container
2. There are negligible intermolecular forces between gas particles
3. Collisions are perfectly elastic and there is no net loss in Kinetic Energy between gas particles

Question 19

What causes less deviation from ideal gas behavior? (Approaching ideal gas behavior)

Answer 19

1. Low pressure: IMF negligible, total volume of particles negligible
2. High temperature: sufficient KE to overcome IMF attractions: negligible.
   * stronger IMF = stronger deviation
   ** larger molecular mass = stronger id-id

Question 20

What is a metallic bond?

Answer 20

It is the electrostatic forces of attraction between metal cations and the sea of delocalised electron

Question 21

Define bond energy

Answer 21

It is the energy required to break one mole of covalent bonds between atoms in a gaseous molecule

Question 22

Define bond length

Answer 22

The distance between the nuclei of the two atoms covalently bonded to each other

Question 23

Describe diamond’s structure and bonding

Answer 23

Each carbon atom forms strong covalent bonds with 4 carbon atoms in a 3D tetrahedral arrangement in a giant covalent lattice structure

Question 24

Describe graphites structure and bonding

Answer 24

Each carbon atom forms strong covalent bonds with 3 other carbon atoms in a 2 D layer of hexagonal carbon rings with weak intermolecular forces of attraction between graphene layers + electric conductivity from highly mobile pi electrons

Question 25

electronegativity

Answer 25

it is the measure of the ability of an element to attract a shared pair of electrons in covalent bond towards itself

Question 26

Hybridisation answering ?

Answer 26

1. 1 s orbital and 1/2/3 p orbitals of (atom) hybridize to form 2/3/4 sp2/3/4 orbitals. 2. There are 2/1 unhybridised o orbitals 3. sp head on overlap with () orbital of (other atom) to form a sigma bond 4. unhybridised p lateral overlap with () orbital of (other atom)

Question 27

order of reaction

Answer 27

X is the order of reaction with respect to A and y is the order of reaction with respect to B in an experimentally determined rate equation