C2 Rates Of Reactions.

Question 0

What is the formula used to calculate the rate of reaction?

Answer 0

Rate of reaction=amount of reactants used or products formed divided by time.

Question 1

How can the rate of a reaction be measured?

Answer 1

Measure how quickly reactants are used up or how quickly products are formed.

Question 4

What is a moderate speed reaction?

Answer 4

Magnesium and acid.

Question 5

How do you know if a reaction is taking place?

Answer 5

Increase in temperature.
Increase or decrease in mass
Appearance

Question 6

Name the three things you can measure to see the rate of reaction.

Answer 6

Decreasing mass of reaction mixture.
Increasing volume of gas being given off.
Decreasing light passing through a solution.

Question 7

How can you measure the rate of reaction by looking at it?

Answer 7

When the product of a reaction is a precipitate.
Look at a mark through the solution and time how long it takes it disappear. Only works when the initial solution is transparent.
The result is subjective as people will disagree when it dissapears.

Question 8

How can the change in mass indicate the rate of reaction?

Answer 8

If a gas is produced you put the reaction on a scale and see the weight go down.
The most accurate method as a scale is very accurate.
However gas is released into the room.

Question 9

How can the volume of a gas given off be a indication of the rate of reaction?

Answer 9

Use a gas syringe to measure the mass of gas given off.

They are quite accurate but can explode if lots of gas is given off.

Question 10

Explain collision theroy.

Answer 10

Reactions take place when the particles come together. They have to hit each other with a high enough amount of energy. This is the reaction energy.

Question 11

In terms of collision theory what causes a reaction to happen more?

Answer 11

Increase the chance of particles colliding.

Increase the energy particles have when they collide.

Question 12

How does increasing the temperature increase the rate of reactions?

Answer 12

The particles move quicker. If they move quicker they will collide more.

Question 13

How does increasing the concentration increase the rate of reaction?

Answer 13

There will be more particles meaning the collisions will be more likely.

Question 14

How does increasing the surface area increase the rate of reaction?

Answer 14

It will mean the particles will collide more with each other.

Question 15

What is a catalyst?

Answer 15

It is a substance which speeds up a reaction, without being changed or used up in the reaction.

Question 16

How does a catalyst increase the rate of reaction?

Answer 16

It lowers the activation energy.

Question 17

Why are catalysts usually powders or pellets?

Answer 17

It increases the surface area.

Question 18

Why are catalysts used in industry?

Answer 18

They increase the rate of reaction which saves money as the plant does’t have to be open for so long and the reaction can happen at lower temperatures. They can be used over and over again.

Question 19

What are the disadvantages of using catalysts?

Answer 19

They can be very expensive and often have to be removed from the product and cleaned.
Different reactions use different catalysts so you may have to have many.
They can harm the environment.
They can be damaged by impurites.

Question 21

What four things does the rate of reaction depend on?

Answer 21

Temperature
Concentration (or pressure for gases)
Catalyst
Surface area of solids( or size of solid particles)

Question 22

What is a slow reaction?

Answer 22

The rusting of iron.