Unit 6-The rate and extent of chemical change Flashcards Preview

Chemistry Gcse AQA 9-1 > Unit 6-The rate and extent of chemical change > Flashcards

Flashcards in Unit 6-The rate and extent of chemical change Deck (42):
1

What is the rate of a chemical reaction?

How fast reactants are changed into products.

2

How can you find out the speed of a reaction?

By the amount of reactant used up and the amount of product formed.

3

What does the rate of reaction depend on?

-Temperature.
-Concentration of a solution or the pressure of a gas.
-Surface area.
-The presence of a catalyst.

4

Why does increasing the temperature increase the rate?

Because the particles move faster and so they collide more frequently.

5

What is a catalyst?

A chemical substance that speeds up a reaction without being used up.

6

Whats the equation for the rate of reaction?

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

7

What is a better way of saying cloudyness?

Its turbidty changes.

8

When can you record a visual change?

When the initial solution is transparent.

9

Whats the problem with visual results?

They are subjective.

10

What happens to the concentration of the equilibrium lies to the right.

The concentration of the products is greater than that of the reactants.

11

What happens to the concentration of it lies to the left?

The concentration of reactants is greater than that of the products.

12

What is a reversible reaction?

A reaction where the products can form the reactants again.

13

What is equilibrium?

When the forward reaction is at the same rate as the backwards reaction.

14

True or false.... equilibrium can only be reached in a closed system.

TRUE.

15

Can equilibrium be reached in an open system?

No.

16

Can equilibrium be reached in a closed system.

Yes.

17

Why can equilibrium only be reached in a closed system?

Because none of the reactants or products can escape.

18

If the equilibrium lies to the right what happens to the concentration?

The concentration of the products is greater than the reactants.

19

If the equilibrium lies to the left what happens to the concentration?

The concentration of the reactants is greater than the products.

20

If a reversible reaction is endothermic on one side what is it on the other side?

Exothermic.

21

If a reaction is exothermic on one side what is it on the other side?

Endothermic.

22

What does the position of equilibrium depend on?

-Temperature.
-Pressure.
-Concentration.

23

What is le chantelier's principle?

The idea that if you change the conditions of a reversible reaction at equilibrium,the system will try to counteract that change.

24

What can le chantelier's principle be used for?

To predict the effect of any changes you make to a reaction system.

25

If you decrease the temperature in a reversible reaction what happens to the equilibrium?

It will move to the exothermic direction to produce more heat.

26

If you raise the temperature in a reversible reaction what happens to the equilibrium?

It will move to the endothermic direction to try and decrease it.

27

Does changing the pressure affect the equilibrium only involving gases?

Yes.

28

How do you work out the mean rate of a reaction?

Quantity of a reactant used over time.

29

What is the activation energy?

The minimum energy particles must have to react.

30

When does a successful collision happen?

When reactant particles collide with enough energy to react.

31

The higher the temperature...

The faster the reaction.

32

How does increasing the concentration increase the rate of a reaction?

It increases the chance of having successful collisions.

33

If a solid is broken what happens to the surface area?

It increases.

34

How does a catalyst work in chemistry?

It provides a different pathway for the reaction that has a lower activation energy.

35

Is the rate of a reaction proportional to the temperature?

No.

36

Why is the rate of a reaction not proportional to the temperature?

Because a small change in the temperature can have a big impact on the rate of reaction.

37

Is the rate of reaction proportional to the concentration?

Yes.

38

Is the rate of a reaction proportional to pressure?

Yes.

39

Is the rate of reaction proportional to surface area of solid reactants?

Yes.

40

What does turbidity mean?

Cloudiness.

41

What is another way of saying cloudiness?

Turbidity.

42

What is a dynamic equilibrium?

A system where both the forward and reverse reactions are taking place simultaneously and at the same rate.