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Question 1

How does a catalyst work?

Answer 1

Catalysts lower the activation energy by providing an alternative reaction pathway, allowing more successful collisions and speeding up the reaction.

Question 2

What do catalysts do and not do?

Answer 2

Catalysts speed up reactions but are not used up in the process.

Question 3

What is the meaning of a reversible reaction?

Answer 3

A reaction that can go in both directions (reactants ⇌ products).

Question 4

What is the collision theory?

Answer 4

For a reaction to occur, reactant particles must collide with enough energy.

Question 5

Give 2 ways to measure the rate of a reaction.

Answer 5

Amount of reactant used up (divided by time) or amount of product formed (divided by time).

Question 6

What is the effect of temperature on rates?

Answer 6

Higher temperatures make particles move faster, increasing the rate of collisions and reaction speed.

Question 7

What effect does a catalyst have on the rate of reaction?

Answer 7

Catalysts lower the activation energy, allowing more successful collisions and speeding up the reaction.

Question 8

What effect does surface area have on the rate of a reaction?

Answer 8

A larger surface area exposes more particles, increasing collisions and speeding up the reaction.

Question 9

What is the effect of concentration/pressure on the rate of reaction?

Answer 9

Higher concentration (solutions) or pressure (gases) increases particle collisions, speeding up the reaction.

Question 10

What is the mass of a substance measured with?

Answer 10

A balance.

Question 11

Volume of a gas is measured with?

Answer 11

A gas syringe or burette.

Question 12

What factors affect rates of a reaction?

Answer 12

Temperature, concentration, pressure, surface area, and catalysts.

Question 13

What is activation energy?

Answer 13

The minimum energy required for particles to react.

Question 14

What does an iron catalyst do?

Answer 14

It helps in the production of ammonia from nitrogen and hydrogen.

Question 15

What’s a platinum catalyst effect?

Answer 15

It also aids in the production of ammonia from nitrogen and hydrogen.

Question 16

What is bond breaking?

Answer 16

An endothermic process where energy is needed to break bonds.

Question 17

What is bond formation?

Answer 17

An exothermic process where energy is released when new bonds are formed.

Question 18

How can you calculate the overall energy change for a reaction?

Answer 18

Using bond energies (Energy of bond breaking - Energy of bond making).

Question 19

What happens if activation energy is low?

Answer 19

Reactions can occur more easily since particles don’t need much energy to react.

Question 20

What is the position of equilibrium?

Answer 20

When the forward and reverse reactions happen at the same rate, and the amounts of reactants and products remain constant.

Question 21

What is Le Chatelier’s Principle?

Answer 21

If a dynamic equilibrium is disturbed, the system shifts to counteract the change.

Question 22

How does changing concentration affect equilibrium?

Answer 22

Adding more reactant shifts the equilibrium to make more product.

Question 23

How does temperature affect equilibrium?

Answer 23

Increasing temperature shifts the equilibrium towards the endothermic reaction, while decreasing it shifts towards the exothermic side.

Question 24

How does changing pressure affect equilibrium?

Answer 24

Increasing pressure shifts the equilibrium to the side with fewer molecules.

Question 25

What happens if you add a catalyst to an equilibrium reaction?

Answer 25

It speeds up the rate at which equilibrium is reached but does not affect the position of equilibrium.

Question 26

Why do particles need to collide with each other?

Answer 26

So bonds can break and new substances can form.

Question 27

Why are powders like icing sugar or flour dangerous?

Answer 27

They have a large surface area, which increases the reaction rate, making them highly flammable.

Question 28

What are the advantages of using catalysts?

Answer 28

They can be used in small amounts repeatedly, saving costs in industrial processes.

Question 29

What is a drawback of catalysts?

Answer 29

Catalysts are specific to the reactions they catalyze and may not work for all reactions.

Question 30

What are catalysts in living things called?

Answer 30

Enzymes (biological catalysts).

Question 31

Where do reactions stop?

Answer 31

When one or both reactants are used up.

Question 32

What is the limiting reactant?

Answer 32

The reactant that is completely consumed in a reaction, stopping the reaction from proceeding further.

Question 33

How can the rate of reaction between marble chips and hydrochloric acid be changed?

Answer 33

By altering the temperature or surface area of the marble chips.

Question 34

How do you measure the rate of reaction on a graph?

Answer 34

Draw a tangent at the point of interest and calculate the gradient (change in volume of gas divided by time).