The Rate and Extent of Chemical Change

Question 1

If you want to measure the rate of a reaction you can measure how fast one of the __________ is formed. What one word completes this sentence?

Answer 1

products

Question 2

If you want to measure the rate of a reaction you can measure how fast one of the __________ is used up. What one word completes this sentence?

Answer 2

reactants

Question 3

A reaction between two particles cannot happen unless the particles have enough __________ when they collide. What is the missing word?

Answer 3

energy

Question 4

If you want to increase the rate of a reaction, should you increase, decrease or make no change to the pressure?

Answer 4

increase

Question 5

True or false? Decreasing the temperature increases the number of collisions between reacting particles.

Answer 5

false

Question 6

Magnesium reacts with acid to give a salt and hydrogen. Will this reaction happen faster using magnesium ribbon or magnesium powder?

Answer 6

magnesium powder

Question 7

Magnesium reacts with acid to give a salt and hydrogen. Why does the reaction happen faster because you use magnesium powder?

Answer 7

Powdered solids have a faster rate of reaction because they have a larger surface area.

Question 8

For a reaction to happen the reacting particles must successfully __________ with one another. What word completes this sentence?

Answer 8

bond

Question 9

True or false? If the same reaction is carried out twice, once at high pressure and once at low pressure, the reaction at low pressure will have a shorter reaction time.

Answer 9

false

Question 10

At ____ ______, there are more particles per unit volume.

Answer 10

higher pressures

Question 11

At higher pressures, there are more ________ per unit volume.

Answer 11

particles

Question 12

the amount of energy needed for the reaction to occur

Answer 12

activation energy

Question 13

Does increasing the surface area of a solid reactant increase, decrease or have no effect on the frequency of collisions between the reacting particles?

Answer 13

increase

Question 14

True or false? Increasing the temperature rarely has an effect on the speed of the reacting particles.

Answer 14

false

Question 15

Does decreasing the temperature increase the rate of a reaction?

Answer 15

no

Question 16

Why does increasing the concentration of reactants increases the reaction rate?

Answer 16

the reactant particles are more crowded so they collide more often

Question 17

What word is used to describe how fast or slow a reaction is?

Answer 17

rate

Question 18

True or false? Catalysts do not change the rates of chemical reactions.

Answer 18

false

Question 19

Does a catalyst increase, decrease or have no effect on the rate of a reaction?

Answer 19

increase

Question 20

An iron catalyst is used to lower the activation energy of a reaction. What effect will this have on the overall energy change of the reaction?

Answer 20

stay the same

Question 21

Catalysts work by lowering the __________ __________. What two words complete the sentence?

Answer 21

activation energy

Question 22

True or false? Different reactions require different catalysts.

Answer 22

true

Question 23

What name is given to any chemical which increases the rate of a chemical reaction?

Answer 23

catalyst

Question 24

True or false? Catalysts are important in industrial processes because they reduce costs.

Answer 24

true

Question 25

Increasing the temperature means that the particles have more energy and so collide __________.

Answer 25

more frequently

Question 26

True or false? Endothermic reactions cannot be catalysed.

Answer 26

false

Question 27

True or False? Every reaction can potentially be catalysed.

Answer 27

true

Question 28

True or false? A catalyst provides a different pathway for a reaction with a higher activation energy for a reaction.

Answer 28

false

Question 29

The number of collisions between the particles of hydrogen and nitrogen is increased by using high pressure and __________.

Answer 29

temperature

Question 30

True or false? Only a small amount of a catalyst is needed to catalyse large amounts of reactants.

Answer 30

true

Question 31

Will decreasing the pressure increase, decrease or have no effect on the number of collisions between the particles of two reacting gases?

Answer 31

decrease

Question 32

How does using a catalyst change the activation energy?

Answer 32

decreases

Question 33

What is the name of a biological catalyst?

Answer 33

enzyme

Question 34

What name is given to a substance that changes the rate of a chemical reaction without being used up in the reaction?

Answer 34

catalyst

Question 35

Will increasing the concentration of reactants increase or decrease the rate of a reaction?

Answer 35

increase the rate of reaction

Question 36

True or false? Changing the temperature will always change the position of the equilibrium for a reversible reaction.

Answer 36

true

Question 37

When products are being made as quickly as reactants, the reaction is said to have reached... what?

Answer 37

equilibrium

Question 38

Equilibrium is reached when the forward reaction happens at exactly the same __________ as the backward reaction. What one word completes this sentence?

Answer 38

rate or speed

Question 39

If the temperature of a reversible reaction is raised, the yield from the exothermic reaction... what?

Answer 39

decreased

Question 40

True or false? Only reversible reactions in open systems can reach equilibrium.

Answer 40

false

Question 41

True or False? Equilibrium can only be reached in a closed system.

Answer 41

true

Question 42

True or false? A reversible reaction is always exothermic in one direction and endothermic in the other.

Answer 42

true

Question 43

We can use Le Chatelier's Principle to predict what will happen to a reversible reaction that is at __________ if we change its temperature, concentration or pressure. What word completes the sentence?

Answer 43

equilibrium

Question 44

This symbol equation shows the production of ammonia: N2 (g) + 3H2 (g) ⇌ 2NH3 (g). Which direction will the equilibrium position shift if the pressure is increased?

Answer 44

to the right

Question 45

For gaseous reactions at equilibrium a decrease in pressure causes the equilibrium position to shift towards the side with the __________ number of molecules. What word is missing from this sentence?

Answer 45

larger

Question 46

If the temperature is raised, the yield from the endothermic reaction... what?

Answer 46

increases

Question 47

A system is at equilibrium. If its temperature is increased, the relative amount of products will __________ for the endothermic reaction. What is missing from this sentence?

Answer 47

increase

Question 48

A system is at equilibrium. If its temperature is decreased, the relative amount of products will __________ for the exothermic reaction. What is missing from this sentence?

Answer 48

increases

Question 49

Here is the symbol equation for the production of ammonia: N2 (g) + __H2 (g) ⇌ 2NH3 (g). What number should be put in the space before H2 (g) to balance this symbol equation?

Answer 49

3

Question 50

True or false? Changing the pressure has no effect on a reversible reaction unless one of the products or reactants is a gas.

Answer 50

true

Question 51

The symbol equation for manufacturing ethanol is: H2O (g) + C2H4 (g) ⇌ C2H5OH (g) The manufacture of ethanol is exothermic. What would happen to the yield of ethanol if the temperature of the reaction is increased?

Answer 51

it would decrease

Question 52

For gaseous reactions at equilibrium an increase in pressure causes the equilibrium position to shift towards the side with the __________ number of molecules. What word is missing from this sentence?

Answer 52

smaller

Question 53

True or false? An equilibrium position always responds to oppose any change in the reaction conditions.

Answer 53

true

Question 54

Here is the symbol equation for the production of ammonia: N2 (g) + 3H2 (g) ⇌ 2NH3 (g). What does the state symbol (g) mean?

Answer 54

gas

Question 55

A reversible reaction is always exothermic in one direction and endothermic in the other. If the temperature is lowered, this will favour the __________ reaction. Which word completes the sentence?

Answer 55

exothermic

Question 56

True or false? Changing the pressure will always change the position of the equilibrium for a reversible reaction.

Answer 56

false

Question 57

Here is the equation for manufacturing ethanol: H2O (g) + C2H4 (g) ⇌ C2H5OH (g) The manufacture of ethanol is exothermic. Where would the position of the equilibrium move if the temperature of the reaction increased?

Answer 57

left

Question 58

This symbol equation shows the production of ammonia: N2 (g) + 3H2 (g) ⇌ 2NH3 (g). Where would the direction of the equilibrium shift if the pressure decreased?

Answer 58

to the left

Question 59

The symbol equation for manufacturing ethanol is: H2O (g) + C2H4 (g) → C2H5OH (g) Increasing the temperature lowers the yield of ethanol because the forward reaction is __________. What is the missing word in this sentence?

Answer 59

exothermic

Question 60

If a change occurs when a system is at equilibrium, the equilibrium position shifts in order to counteract the change. This is known as __________'s Principle. What name completes the sentence?

Answer 60

Le Chatelier

Question 61

the rate of a chemical reaction is how fast the _________ are changed into _________.

Answer 61

reactants are changed into products

Question 62

example of slow reactions

Answer 62

iron rusting

Question 63

example of moderate speed reaction

Answer 63

metal magnesium react with an acid to produce bubbles

Question 64

example of fastest reaction

Answer 64

fireworks exploding

Question 65

steeper the line on the graph the ________ the rate of reaction.

Answer 65

faster

Question 66

why does the line on the line graph become less steep over time

Answer 66

reactants are slowly used up

Question 67

rate of chemical reaction depends on…. what?

Answer 67

- collision frequency - energy transferred during a collision

Question 68

activation energy

Answer 68

the amount of energy needed for the reaction to occur

Question 69

position of equilibrium depends on what conditions?

Answer 69

- temperature - pressure - concentration

Question 70

what is Le Chatelier’s Principle used to predict?

Answer 70

the effect of any change you make to a reaction system

Question 71

If you increase the pressure, the equilibrium tries to reduce it. It moved in the direction where there are ______ ____________ __ ___.

Answer 71

fewer molecules of gas

Question 72

If you decrease the pressure, the equilibrium tries to increase it. It moves in the direction where there are _____ __________ __ ___.

Answer 72

more molecules of gas

Question 73

If you change the concentration of either the reactants or the products, the system will __ ________ __ __ ___________.

Answer 73

no longer be at equilibrium

Question 74

The rate of a chemical reaction tells us how _______ _ _______ _______ or how quickly a reactant is used up.

Answer 74

quickly a product is formed

Question 75

The rate of a chemical reaction tells us how quickly a product is formed or how ______ _ ________ __ _____ __

Answer 75

quickly a reactant is used up

Question 76

For chemical reactions to occur, reactant particles must ________ ___ ______ _______.

Answer 76

collide with enough energy

Question 77

what are reactant particles that collide with enough energy called?

Answer 77

successful collisions

Question 78

Name 4 factors that affect the rate of a chemical reaction

Answer 78

- concentration and pressure - catalyst - surface area - temperature

Question 79

large lumps of a solid have a ______ ______ __ ______ ______.

Answer 79

small surface area to volume ratio

Question 80

In a closed system, reversible reactions can reach…

Answer 80

dynamic equilibrium