Rate Of Reaction

Question 1

What does the collision theory show?

Answer 1

Collision theory explains how reactants happen and why they happen at different rates

Question 2

What needs to happen for particle collision to occur?

Answer 2

Particles must collide for chemical reactions to happen

Importantly, these collisions must happen with enough energy

Question 3

What is activation energy?

Answer 3

The activation energy is the minimum energy which particles must collide with in order to cause a chemical reaction

Question 4

How do we increase the rate of reaction?

Answer 4

We can increase the rate of reaction by increasing the number of collisions or the energy of reactant particles

Question 5

What are the four main factors that affect reaction rates?

Answer 5

Temperature - increasing the temperature increases the rate at which collisions happen
Concentration - increasing the concentration increase the collisions frequency. This increases the rate of reaction
Surface area - this increases the collision frequency
Pressure - increasing the pressure increase the collisions frequency

Question 6

What does the collision theory say the minimum requirements are for a reaction to happen?

Answer 6

Particles must collide

The energy of particles must exceed the activation energy

Question 7

Rate of reaction = ?

Answer 7

Rate of reaction = change in y / change in x

The steeper the gradient of the line, the faster the reaction

Question 8

The key features of a concentration - time graphs:
Larger gradient = ?
Smaller gradient = ?
Zero gradient = ?

Answer 8

Larger gradient = faster rate of reaction
Smaller gradient = slower rate of reaction
Zero gradient = reaction has finished

Question 9

According to collision theory, how can we increase the rate of reaction?

Answer 9

Increase the frequency of collisions

Increase the energy of reacting particles

Question 10

What are the effects of increasing the temperature of a chemical reaction?

Answer 10

Increased frequency of collisions
Increased rate of reaction
Increased energy of reactant particles

Question 11

What do all chemical reactions involve?

Answer 11

All chemical reactions involve bond breaking and bond making

Question 12

What is the definition of an exothermic reaction?

Answer 12

A reaction where energy is released into the surroundings. You would see an increase in temperature

Question 13

What is the definition of an endothermic reaction?

Answer 13

A reaction where energy is taken (absorbed) from the surroundings. You would see a decrease in temperature

Question 14

Is bond making exothermic or endothermic?

Answer 14

Exothermic

Question 15

Is bond breaking exothermic or endothermic?

Answer 15

Endothermic

Question 16

Overall, what happens in a exothermic reaction?

Answer 16

Overall, more heat energy is released in the making of bonds in the products than is needed to break the bonds in the reactants

Question 17

Overall, what happens in a endothermic reaction?

Answer 17

Overall, more heat energy needed in the breaking of bonds in the reactants than is released in making the bonds in the products