Chapter 10

Question 1

What does a rate of reaction measure?

Answer 1

It measure how quickly a reactant is being used up, or how quickly a product is being formed.

Question 2

What is the equation for rate of reaction?

Answer 2

rate= change in concentration/ time

Question 3

What happens when the concentration or pressure is increased?

Answer 3

Means that there are more particles in a given volume, which increases the chance of successful collisions, increasing rate.

Question 4

How can the rate of reaction be calculated?

Answer 4

By measuring the gradient of a concentration-time graph.

Question 5

What is a catalyst?

Answer 5

A catalyst is a substance that increases the rate of a chemical reaction by providing an alternative reaction route with a lower activation energy, without being used up.

Question 6

What is a homogenous catalyst?

Answer 6

Are in the same physical states as the reactants.

Question 7

What is a heterogenous catalyst?

Answer 7

Are in the different physical states as the reactants.

Question 8

What are the benefits of using a catalyst?

Answer 8

• lower temperatures are needed
• higher atom economy of reactions
• increased reaction rate means products are made faster
• fewer pollutants produced

Question 9

What is the impact on the environment or industries?

Answer 9

• reduced energy demand from the combustion of fossil fuels, resulting in a reduction of CO2 emissions
• reduced waste, higher percentage of useful products made from raw materials
• uses less energy, cut costs and increase profits
• reduces the number of pollutants released into the environment.

Question 10

What happens in a reversible reaction?

Answer 10

The forward and backward reaction proceed at the same rate. The concentration of reactions and products remain constant. Happen in close systems.

Question 11

What does Le Chatelier’s principle state?

Answer 11

That if a system at equilibrium is distributed, the equilibrium moves in that direction to oppose the change.

Question 12

What does Le Chatelier’s principle state for temperature?

Answer 12

Increase temperature - equilibrium will shift to the reaction which is endothermic.
Decrease temperature - equilibrium will shift to the reaction which is exothermic.

Question 13

What does Le Chatelier’s principle state for pressure?

Answer 13

Increase pressure - equilibrium will shift to the side where there are fewer gas molecules
Decrease pressure - equilibrium will shift to the side where there are more gas molecules

Question 14

What does Le Chatelier’s principle state for concentration?

Answer 14

Increase concentration - equilibrium will shift to the side opposite to where the concentration is there already.
Decrease concentration - equilibrium will shift to the same side to where the concentration is there.

Question 15

What does Le Chatelier’s principle state for a catalyst?

Answer 15

It has no effect on the position of the equilibrium, but will increase the rate of reaction for both reactions equally.

Question 16

What is equilibrium constant equation (kc)?

Answer 16

aA + bB —— cC + dB
kc= (C)c (D)d/ (A)a (B)b
to the power of little letter

Question 17

What does the magnitude of Kc mean?

Answer 17

It tells the relative properties of reactants and products in the equilibrium system. If Kc is less than 1 it lies on the left hand side of equilibrium. If Kc is more than 1 it lies on the right hand side of equilibrium.