Kinetics

Question 1

What 2 factors are important in terms of particles, for them to collide in order to react?

Answer 1

Orientation

Energy

Question 2

What happens to the molecules if you increase the temperature of a reaction?

Answer 2

Speed and energy of molecules increases meaning collisions are more likely.

Question 3

What happens to the molecules if you increase the concentration of a solution in a reaction?

Answer 3

There are more molecules present in a given volume so collisions are more likely and the reactions rate is faster.
However the reaction will slow over time as reactants are used up.

Question 4

What is kinetics the study of?

Answer 4

Factors that affects rates of chemical reactions.

Question 5

What is activation energy ?

Answer 5

Minimum energy that a particle needs in order to react.

Question 6

What is the Maxwell-Boltzmann distribution?

Answer 6

The distribution of energies of the molecules in a gas or liquid.

Question 7

What is a closed system?

Answer 7

One where the reactants and products can’t escape.

Question 8

When temperature is lowered, how does the shape of the maxwell-Boltzmann distribution change?

Answer 8

Peak is shifted to the left and the peak is higher.

Question 9

Which catalyst is used in the Haber process?

Answer 9

Iron

Question 10

Which catalyst is used in the Ostwald process?

Answer 10

Platinum and rhodium.

Question 11

Which catalyst is used to make hardening fats with hydrogen?

Answer 11

Nickel.

Question 12

Which catalyst is used when cracking hydrocarbon chains from crude oil?

Answer 12

Aluminium oxide and silicon dioxide or zeolite.

Question 13

What catalyst is used in catalytic converters in car exhausts?

Answer 13

Platinum and rhodium.

Question 14

Which catalyst is used in the hydration of ethene to produce ethanol?

Answer 14

H+ absorbed on solid silica

Phosphoric acid, H3PO4

Question 15

Which catalyst is used in esterification?

Answer 15

H+

Question 16

Which substances are converted by catalytic converters?

Answer 16

Carbon monoxide and nitrogen oxides

Hydrocarbons and nitrogen oxides

Question 17

What are the two steps of a reaction occurring on a catalyst?

Answer 17

Absorption

Desorption

Question 18

What does the study of kinetics enable chemists to determine?

Answer 18

How a change in conditions affects the speed of a chemical reaction.

Question 19

How and why does the concentration of a solution affect the rate of reaction?

Answer 19

The higher the conc. the faster the reaction.

Particles are closer together so there are more frequent collisions.

Question 20

How and why does the surface area of a solid affect the rate of reaction?

Answer 20

The greater the surface area, the faster reaction.
There are more particles exposed at the surface that can be collided with, and so there are more frequent successful collisions.

Question 21

How and why does the pressure of gases affect the rate of reaction?

Answer 21

The higher the pressure, the faster the reaction.

Particles are closer together and so there are more frequent collisions.

Question 22

How and why does the temperature affect the rate of reaction?

Answer 22

Higher the temp. the faster the reaction.
Particles have more energy and so a greater proportion of the collisions are successful. Particles also move faster so collisions are more frequent.

Question 23

How and why does a catalyst affect the rate of reaction?

Answer 23

Increases the rate of reaction by providing an alternative route with a lower activation energy so a greater proportion of the collisions are successful.