Chemistry Unit 1

Question 1

What is lattice enthalpy?

Answer 1

The enthalpy change when one mole of an ionic compound is converted to gaseous ions.

Question 2

What is entropy?

Answer 2

The measure of disorder

Question 3

What is an asymmetric centre?

Answer 3

A carbon with four different atoms or groups attached.

Question 4

What does optically active mean?

Answer 4

It rotates a plane of plane polarised light.

Question 5

Why would a molecule have more than one pKa value?

Answer 5

It has more than one -COOH group

Question 6

What is meant by the term hydrogenation?

Answer 6

Addition of a hydrogen molecule across C=C

Question 7

Name a catalyst used in the hardening of unsaturated fatty acids.

Answer 7

Nickel

Question 8

How do you “quench” a solution

Answer 8

Add excess water

Question 9

Define lattice enthalpy

Answer 9

The enthalpy required to convert 1 mole of ionic solid into gaseous ions

Question 10

What is the standard enthalpy of solution?

Answer 10

The enthalpy change when 1 mole of a solute dissolves in water

Question 11

Define standard enthalpy of hydration

Answer 11

The enthalpy change when 1 mole of gaseous ions converted into 1 mole of aqueous ions.

Question 12

What is the equation for lattice enthalpy?

Answer 12

ΔHsol = ΔHlatt + ΔHhyd

Question 13

How do you find enthalpy of formation?

Answer 13

ΔH = Σ products - Σ reactants

Question 14

How do you find enthalpy of combustion?

Answer 14

ΔH = Σ Reactants - Σ Products

Question 15

How do you find bond enthalpy?

Answer 15

ΔH = Σ bonds broken - Σ bonds formed

Question 16

How do you find entropy?

Answer 16

ΔS = Σ Products - Σ Reactants

Question 17

How do you find free energy (ΔG)?

Answer 17

ΔG = ΔH - TΔS

Question 18

Define Brønsted-Lowry acid

Answer 18

Proton donors

Question 19

Define Brønsted-Lowry base

Answer 19

Proton acceptor

Question 20

Define monobasic acid

Answer 20

An acid that releases one H+ ion per molecule.

Question 21

Define dibasic acid

Answer 21

An acid that releases two
H⁺ ions per molecule

Question 22

Equation of strong acids

Answer 22

[H⁺] = [HA]

Question 23

Equation of alkalis

Answer 23

[H⁺]= Kw / [OH^-]

Question 24

What are optical isomers

Answer 24

Molecules which exist as non-superimposable mirror images

Question 25

What is K_w equal to?

Answer 25

[OH][H]

Question 26

What is transesterfication?

Answer 26

A reaction where the alkyl group of an ester is exchanged for the alkyl groups of an alcohol.