Unit 2 - Kinetics

Question 1

Is bond breaking exothermic or endothermic?

Answer 1

Endothermic

Question 2

Is bond making exothermic or endothermic?

Answer 2

Exothermic

Question 3

What effect will increasing the surface area of a reactant have on the reaction?

Answer 3

Increase the rate of reaction

Question 4

what effect will decreasing the temperature of a reaction have on its rate?

Answer 4

It will decrease the rate of reaction

Question 5

what effect will increasing the concentration of a reactant in solution have on the rate of the reaction

Answer 5

It will increase the rate of the reaction

Question 6

what effect will decreasing the pressure of a gas reactant have on the rate of its reaction

Answer 6

It will decrease the rate of reaction

Question 7

what effect will decreasing the surface area of solid reactants have on their rate of reaction

Answer 7

It will decrease their rate of reaction

Question 8

How do catalyst work and what effect do they have on the rate of a reaction?

Answer 8

Catalysts provide an alternative reaction pathway with a lower activation energy. They speed up the rate of reactions as more particles will have energy greater than or equal to the activation energy

Question 9

Draw a Maxwell Boltzmann distribution graph of a reaction showing activation energy and activation energy with a catalyst (4 marks)

Answer 9

1. Correctly drawn curve
2. Correctly labelled x and y axis
3. Vertical line showing activation energy (accept Ea)
4. Vertical line on the left of activation energy showing activation energy with catalyst (accept Ea cat)

Question 10

What does the peak of a Maxwell Boltzmann distribution graph show?

Answer 10

The most probable energy of reactant particles

Question 11

Where would you expect to find the mean energy of a particle on a Maxwell Boltzmann distribution graph?

Answer 11

To the right of the peak

Question 12

For particles to react, how must they interact with each other? (2 marks)

Answer 12

1. They must collide with the minimum activation energy

2. They must collide in the correct orientation

Question 13

If two reactant particles collide, will they react?

Answer 13

Not necessarily - they must have at least the activation energy and be in the correct orientation

Question 14

What does the term homogeneous mean when referring to catalysts?

Answer 14

The catalyst is in the same phase (or state) as the reactants

Question 15

What does the term heterogeneous mean when referring to catalysts?

Answer 15

The catalyst is in a different phase (or state) as the reactants

Question 16

Draw a curve on a Maxwell Boltzmann distribution graph of a reaction and a second curve showing the same reaction at a higher temperature (3 marks)

Answer 16

1. Correctly drawn curves
2. Correctly labelled x and y axis
3. correctly labelled curves (accept T1 and T2)

Question 17

Define endothermic

Answer 17

A reaction that takes in energy

Question 18

Define exothermic

Answer 18

A reaction that gives off energy

Question 19

State the first law of thermodynamics

Answer 19

Energy can neither be created nor destroyed. It can only change forms

Question 20

what does the equation q=mCΔT express and what are the units? (4 marks)

Answer 20

Heat energy(J) = mass(g) x specific heat capacity(JgK) x change in temperature(k)