7.4 Rates of Reaction

Question 1

How can you measure the rate of a reaction?

Answer 1

The rate at which a reactant is used up, The rate at which a product is formed

Question 2

Name 2 factors which can affect the rate of a reaction.

Answer 2

Temperature/pressure/concentration/SA/ catalysts

Question 3

What has to happen to particles for a reaction to occur?

Answer 3

Collide with enough energy

Question 4

Define the term activation energy.

Answer 4

The amount of energy required for them to react

Question 5

How can you measure the rate of a reaction when a solid dissolves?

Answer 5

Mass of substance used up

Question 6

How can you measure the rate of a reaction when a gas is given off?

Answer 6

Volume of gas given off

Question 7

What are the units for rate of reaction?

Answer 7

g/s orcm3/s or mol/s

Question 8

Which variable is plotted on the x-axis of a rate graph?

Answer 8

Independent / Time

Question 9

What variable can be found on the y-axis of a rate graph?

Answer 9

Dependent / Amount of product formed or amount of reactant used

Question 10

How can you calculate the average rate across a period of time?

Answer 10

Change in Y / Change in X

Question 11

What is a tangent?

Answer 11

A tangent is a straight line drawn on a curve

Question 12

What information does a tangent provide?

Answer 12

The rate of reaction at a specific point

Question 13

What does it mean when the curve on a rate graph gets steeper?

Answer 13

The rate of reaction is increasing

Question 14

What does it mean when the curve on a rate graph gets shallower?

Answer 14

The rate of reaction is decreasing

Question 15

How can you tell that a reaction has finished from a rate graph?

Answer 15

The line becomes constant/ horizontal

Question 16

What is the rate of reaction?

Answer 16

The rate of a reaction is how quickly the products are being made

Question 17

Name 2 factors that affect the rate of a reaction.

Answer 17

Temperature/concentration/SA/pressure

Question 18

What is the scientific term for movement energy?

Answer 18

Kinetic Energy

Question 19

When temperature is increased what energy store increases in the particles?

Answer 19

Thermal Energy

Question 20

What does the term activation energy mean?

Answer 20

The minimum amount of energy that the reactant particles must collide with to cause the reaction to occur

Question 21

How does increasing temperature increase the rate of a reaction?

Answer 21

The particles have more kinetic energy

Question 22

How does increasing pressure increase the rate of a reaction?

Answer 22

The particles are closer together and so more likely to collide

Question 23

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

Answer 23

There are more reactants available to react

Question 24

Define the term activation energy.

Answer 24

The amount of energy needed for a reaction to occur

Question 25

What does a reaction profile show?

Answer 25

The energy changes during a chemical reaction

Question 26

In an endothermic reaction- which has higher energy, reactants or products?

Answer 26

Products

Question 27

In an exothermic reaction- which has higher energy, reactants or products?

Answer 27

Reactants

Question 28

Is energy absorbed or released when new bonds are made?

Answer 28

Released

Question 29

Is energy absorbed or released when bonds are broken?

Answer 29

Absorbed

Question 30

What decides if a reaction is exothermic or endothermic?

Answer 30

The difference in energy needed to break bonds and the energy released when new bonds form

Question 31

What equipment could you use to tell if a reaction is exothermic or endothermic?

Answer 31

Thermometer

Question 32

What is a catalyst?

Answer 32

A substance which increases the rate of a chemical reaction without being used up itself.

Question 33

How does a catalyst increase the rate of a reaction?

Answer 33

Provides an alternate pathway for the reaction to occur

Question 34

What is an enzyme?

Answer 34

A biological catalyst

Question 35

What are enzymes made from?

Answer 35

Proteins

Question 36

Why is the shape of the active site of an enzyme important?

Answer 36

Complimentary to the substrate

Question 37

What is the ‘lock and key’ model?

Answer 37

The enzyme and substrate have specific complementary shapes

Question 38

Name 2 factors that can affect the effectiveness of an enzyme.

Answer 38

Temperature and pH

Question 39

What are conditions in the human stomach like?

Answer 39

Acidic

Question 40

What is a reversible reaction?

Answer 40

A reaction that can produce products, but the products can also react to create the reactants

Question 41

What is a dynamic equilibrium?

Answer 41

The forward and backward reaction occur at the same rate?

Question 42

HT: In which direction does an equiliubrium shift if temperature is increased?

Answer 42

In the endothermic direction

Question 43

HT: In which direction does an equiliubrium shift if temperature is decreased?

Answer 43

In the exothermic direction

Question 44

HT: In which direction does an equiliubrium shift if pressure is increased?

Answer 44

In the direction of fewer particles

Question 45

HT: In which direction does an equiliubrium shift if pressure is decreased?

Answer 45

In the direction of more particles

Question 46

HT: In which direction does an equiliubrium shift if concentration of reactants is increased?

Answer 46

In the direction of the products

Question 47

HT: In which direction does an equiliubrium shift if concentration of products is increased?

Answer 47

In the direction of the reactants

Question 48

What colour change would you expect to see when iodine is added to starch?

Answer 48

From brown to blue - black

Question 49

Why does increasing surface area increase the rate of a chemical reaction?

Answer 49

It increases the available particles for the reaction

Question 50

Why does increasing temperature increase the rate of a chemical reaction?

Answer 50

It increases the energy of the particles

Question 51

What is a tangent?

Answer 51

A straight line drawn on a curve

Question 52

How does a catalyst increase the rate of reaction?

Answer 52

Gives the reaction an alternate pathway and increases the rate.

Question 53

What term matches this definition? Energy required to start a reaction

Answer 53

Activation energy

Question 54

What term matches this definition? Part of an enzyme where the substrate becomes a product

Answer 54

Active site

Question 55

What term matches this definition? The chemical energy stored in the bonds between atoms

Answer 55

Bond energy

Question 56

What term matches this definition? Substance which speeds up a reaction

Answer 56

Catalyst

Question 57

What term matches this definition? Particles must collide to cause a reaction

Answer 57

Collision theory

Question 58

What term matches this definition? Forward and backwards reactions occur at the same rate

Answer 58

Dynamic equilibrium

Question 59

What term matches this definition? Reaction which absorbs energy from the surroundings

Answer 59

Endothermic

Question 60

What term matches this definition? A biological catalyst

Answer 60

Enzyme

Question 61

What term matches this definition? Reaction which releases energy to the surroundings

Answer 61

Exothermic

Question 62

HT: What term matches this definition? Dynamic equilibrium can shifts due to external factors

Answer 62

Le Chatelier’s principle

Question 63

What term matches this definition? Model which explains how enzymes are specific to their substrate

Answer 63

Lock and key model

Question 64

What term matches this definition? Diagram to show the energy changes during a reaction

Answer 64

Reaction profile

Question 65

What term matches this definition? Reaction where products can react to produce the reactants

Answer 65

Reversible reaction

Question 66

What term matches this definition? The substance an enzyme works on

Answer 66

Substrate

Question 67

What term matches this definition? The ratio of surface area to volume

Answer 67

Surface area:volume