Chemistry

Question 1

How does particle size affect reaction rate?

Answer 1

Particle size decrease, larger total surface area to volume ratio, collision frequency increases, successful collision frequency increases, reaction rate increases.

Reaction Kinetics, pg. 12

Question 2

How does concentration affect reaction rate?

Answer 2

Higher concentration, more reacting particles per unit volume, collision frequency increases, successful collision frequency increases, reaction rate increases.

Reaction Kinetics, pg. 16

Question 3

How does pressure affect reaction rate?

Answer 3

Higher gas pressure, more reacting particles per unit volume, collision frequency increases, successful collision frequency increases, reaction rate increases.

Reaction Kinetics, pg. 17

Question 4

How does temperature affect reaction rate?

Answer 4

Higher temperature, higher kinetic energy of reacting particles, greater proportion of reacting particles collide with energy greater than or equal to activation energy, successful collision frequency increases, reaction rate increases.

Reaction Kinetics, pg. 18

Question 5

How do catalysts affect reaction rate?

Answer 5

Catalyst provides lower activation energy alternative pathway, greater proportion of reacting particles collide with energy greater than or equal to lowered activation energy, successful collision frequency increases, reaction rate increases.

Reaction Kinetics, pg. 20

Question 6

How does reactant concentration affect equilbrium position?

Answer 6

When more reactant X is added, by Le Chatelier’s principle, forward reaction favoured to remove some excess reactant X. Equilibrium position shifts right.

Chemical Equilibrium, pg. 53

Question 7

How does pressure affect equilibrium position?

Answer 7

When pressure increased, by Le Chatelier’s principle, for/backward reaction favoured to decrease number of moles of gaseous particles in order to decrease pressure, equilibrium posiiton shifts left/right.

Chemical Equilibrium, pg. 55

Question 8

How does temperature affect equilibrium position?

Answer 8

When temperature increased, energy added, by Le Chatelier’s principle, endothermic reaction (ΔH>0) favoured to absorb some heat energy, the for/backward reaction favoured, equilibrium position shifts left/right.

When temperature decreased, energy removed, by Le Chatelier’s principle, exothermic reaction (ΔH<0) favoured to release some heat energy, the for/backward reaction favoured, equilibrium position shifts left/right.

Chemical Equilibrium, pg. 58

Question 9

How do catalysts affect equilibrium position?

Answer 9

When catalyst added, activation energy of both forward and backward reactions lowered, both reaction rates increase by the same extent, new equilibrium reached in shorter time, no change to equilibrium position.

Chemical Equilibrium, pg. 60

Question 10

Name the reactivity series

Answer 10

Please Stop Calling Mary A Clumsy Zebra It’s Lame How Can She Gallop

Potassium Sodium Calcium Magnesium Aluminum Carbon Zinc Iron Lead Hydrogen Copper Silver Gold

Question 11

What happens to OH- in electrolysis?

Answer 11

4OH- (a1) : O2 (g) + 2H2O (l) + 4e-

Question 12

1-4 C fraction?

Answer 12

Refinery gas

Question 13

5-10 C fraction?

Answer 13

Petrol/naphtha

Question 14

10-16 C fraction?

Answer 14

Kerosene

Question 15

13-25 C fraction?

Answer 15

Gas oil

Question 16

> 25 C fraction?

Answer 16

Residue

Question 17

How does carbon chain length affect b.p./m.p.?

Answer 17

Carbon chain length increases, larger electron cloud more easily polarised, more energy needed to overcome stronger london forces, b.p./m.p. increases.

Question 18

How does degree of branching affect m.p./b.p.?

Answer 18

Greater branching, smaller surface area in contact with other molecules, less energy needed to overcome weaker london forces, m.p./b.p. decreases.

Question 19

Describe combustion/oxidation of alkanes/alkenes

Answer 19

Alkane/alkene + Oxygen : Carbon dioxide + Water

Question 20

Describe halogenation of alkanes and conditions

Answer 20

Alkane (CH3) + Halogen (X2) : CH3X + HX
Presence of UV light

Question 21

Describe cracking process and conditions

Answer 21

Long chain alkanes : short chain alkenes + short chain alkanes OR H2

Alumina catalyst, 500C, 1atm

Question 22

Describe hydrogenation/reduction of alkenes

Answer 22

Alkene + H2 : Alkane

Platinum catalyst, 150C, high atm

Question 23

Describe halogenation of alkenes, conditions and observations

Answer 23

Alkene + Cl2/Br2 : Haloalkane

Dark room, rtp

Cl2/Br2 decolourised

Question 24

Describe hydration of alkenes and conditions

Answer 24

Alkene + Steam : Alcohol

Phosphoric acid catalyst, 300C, 60 atm

Question 25

How does alcohol classification affect b.p./m.p?

Answer 25

Tertiary alcohols are surrounded by large alkyl groups, less energy needed to overcome less extensive hydrogen bonding network, m.p./b.p. decreases.

Question 26

How does carbon chain length affect alcohol solubility?

Answer 26

Longer carbon chain hinders formation of hydrogen bonds between water molecules and alcohol molecules, so they are less soluble.

Question 27

Yeast reaction?

Answer 27

C6H12O6 : 2C2H5OH + 2CO2

Question 28

Describe oxidation of alcohols to carboxylic acids and conditions

Answer 28

Alcohol + 2[O] : Carboxylic acid + water

KMNO4/K2Cr2O7 catalyst, heat under reflux

Question 29

Describe esterification/condensation reaction between alcohols and carboxylic acids and conditions

Answer 29

Alcohol + Carboxylic acid : Ester + water

H2SO4 catalyst, heat under reflux

Question 30

Describe hydrolysis of esters and conditions

Answer 30

Ester + water : Alcohol + Carboxylic acid

Dilute HCl catalyst, heat under reflux