C8.5 - The effect of catalysts

Question 1

Sometimes when might a reaction only work?

Answer 1

Sometimes a reaction might only work if you use very high:
1. Temperatures
Or,
2. Pressures

Question 2

Sometimes a reaction might only work if you use very high temperatures or pressures.
What can this cost industry?

Answer 2

This can cost industry a lot of money

Question 3

Sometimes a reaction might only work if you use very high temperatures or pressures.
This can cost industry a lot of money.
However, how can you speed up some reactions and reduce energy costs?

Answer 3

You can:
1. Speed up some reactions
2. Reduce energy costs
by using catalysts

Question 4

Catalyst

Answer 4

A catalyst is a substance that speeds up a chemical reaction by providing a different pathway for the reaction that has a lower activation energy

Question 5

Why can a catalyst be used over and over again?

Answer 5

A catalyst can be used over and over again, because it is not used up in the reaction

Question 6

What is needed for different reactions?

Answer 6

Different catalysts are needed for different reactions

Question 7

Different catalysts are needed for different reactions.

What do many of the catalysts used in industry involve?

Answer 7

Many of the catalysts used in industry involve transition metals

Question 8

Different catalysts are needed for different reactions.
Many of the catalysts used in industry involve transition metals.
Examples of transition metals that are used in industry as catalysts

Answer 8

Examples of transition metals that are used in industry as catalysts are:

1. Iron
2. Platinum

Question 9

Iron is used to make what?

Answer 9

Iron is used to make ammonia

Question 10

Platinum is used to make what?

Answer 10

Platinum is used to make nitric acid

Question 11

What form are catalysts normally used in?

Answer 11

Catalysts are normally used in the form of:
1. Powders
2. Pellets
Or,
3. Fine gauzes

Question 12

Catalysts are normally used in the form of powders, pellets, or fine gauzes.
What does this give them?

Answer 12

This gives them the biggest possible surface area to volume ratio

Question 13

Where are catalysts?

Answer 13

Catalysts are:

1. All around you
2. In the natural world
3. In industry

Question 14

Catalysts are all around you, in the natural world and in industry.
What are the biological catalysts in living things called?

Answer 14

The biological catalysts in living things are called enzymes

Question 15

Catalysts are all around you, in the natural world and in industry.
The biological catalysts in living things are called enzymes.
What are these enzymes?

Answer 15

These enzymes are large protein molecules that are folded into intricate shapes to accommodate the reactant molecules called substrates

Question 16

Catalysts are all around you, in the natural world and in industry.
The biological catalysts in living things are called enzymes.
These enzymes are large protein molecules that are folded into intricate shapes to accommodate the reactant molecules called substrates.
Enzymes are incredibly efficient what?

Answer 16

Enzymes are incredibly efficient catalysts

Question 17

The transition metals platinum and palladium are used in what?

Answer 17

The transition metals:
1. Platinum
2. Palladium
are used in the catalytic converters in cars

Question 18

The transition metals platinum and palladium are used in the catalytic converters in cars.
How is their surface area to volume ratio maximised?

Answer 18

Their surface area to volume (SA :V) ratio is maximised, as they are coated onto a honeycombed support

Question 19

What do catalysts not do?

Answer 19

Catalysts do not:
1. Increase the frequency of collisions between reactant particles
Nor do they
2. Make collisions any more energetic

Question 20

Catalysts do not increase the frequency of collisions between reactant particles, nor do they make collisions any more energetic.
How do they increase rates of reaction?

Answer 20

Catalysts increase rates of reaction by providing an alternative reaction pathway to the products, with a lower activation energy than the reaction without the catalyst present

Question 21

Catalysts increase rates of reaction by providing an alternative reaction pathway to the products, with a lower activation energy than the reaction without the catalyst present.
So with a catalyst, a higher proportion of the reactant particles have what?

Answer 21

With a catalyst, a higher proportion of the reactant particles have sufficient energy to react

Question 22

With a catalyst, a higher proportion of the reactant particles have sufficient energy to react.
What does this mean?

Answer 22

This means that the:

1. Frequency of effective collisions, collisions that result in a reaction, increases
2. Rate of reaction speeds up

Question 23

Catalysts are often what?

Answer 23

Catalysts are often very expensive precious metals

Question 24

Catalysts are often very expensive precious metals.

What are gold, platinum and palladium?

Answer 24

1. Gold
2. Platinum
3. Palladium
   are all costly

Question 25

Catalysts are often very expensive precious metals. Gold, platinum and palladium are all costly, but are the most effective catalysts for particular reactions. What is it usually cheaper to do?

Answer 25

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one

Question 26

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because to get the same rate of reaction without a catalyst would require higher temperatures and/or pressures. So what do catalysts do?

Answer 26

So catalysts: 1. Save money 2. Help the environment

Question 27

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because to get the same rate of reaction without a catalyst would require higher temperatures and/or pressures. So catalysts save money and help the environment, because using high temperatures and pressures often involve burning fossil fuels. So what does operating at lower temperatures and pressures do?

Answer 27

Operating at lower temperatures and pressures: 1. Conserves these non-renewable resources 2. Stops more carbon dioxide entering the atmosphere when they are burnt

Question 28

Climate change

Answer 28

Climate change is the change in global weather patterns that could be caused by excess levels of greenhouse gases in the atmosphere

Question 29

Not only does a catalyst speed up a reaction, but what does it also do?

Answer 29

Not only does a catalyst speed up a reaction, but it also does not get used up in the reaction

Question 30

Not only does a catalyst speed up a reaction, but it also does not get used up in the reaction, so a tiny amount of catalyst can be used to speed up a reaction over and over again. However, what do the catalysts used in chemical plants eventually become?

Answer 30

The catalysts used in chemical plants eventually become 'poisoned'

Question 31

The catalysts used in chemical plants eventually become 'poisoned,' so that they do not work anymore. Why does this happen?

Answer 31

The catalysts used in chemical plants eventually become 'poisoned,' so that they do not work anymore, because impurities in the reaction mixture: 1. Combine with the catalyst 2. Stop it working properly

Question 32

Why do catalysts not appear in the balanced equation for a reaction, but can be written above the reaction arrow?

Answer 32

Catalysts do not appear in the balanced equation for a reaction, but can be written above the reaction arrow, because: 1. Catalysts change only the rate of reactions 2. The products do not change

Question 33

A catalyst is a substance that speeds up a chemical reaction by providing a different pathway for the reaction that has a lower activation energy. The catalyst is what at the end of the reaction?

Answer 33

The catalyst is chemically unchanged at the end of the reaction

Question 34

Catalysts are normally used in the form of powders, pellets, or fine gauzes. This gives them the biggest possible surface area to volume ratio, making them what?

Answer 34

This gives them the biggest possible surface area to volume ratio, making them as effective as possible

Question 35

Catalysts are normally used in the form of powders, pellets, or fine gauzes. This gives them the biggest possible surface area to volume ratio, making them as effective as possible, because the reactions they catalyse often involve what?

Answer 35

This gives them the biggest possible surface area to volume ratio, making them as effective as possible, because the reactions they catalyse often involve gases reacting on their surfaces

Question 36

Catalysts are all around you, in the natural world and in industry. The biological catalysts in living things are called enzymes. These enzymes are large protein molecules that are folded into intricate shapes to accommodate the reactant molecules called substrates. Enzymes are incredibly efficient catalysts and work at what temperatures?

Answer 36

Enzymes: 1. Are incredibly efficient catalysts 2. Work at relatively low temperatures

Question 37

Catalysts are all around you, in the natural world and in industry. The biological catalysts in living things are called enzymes. These enzymes are large protein molecules that are folded into intricate shapes to accommodate the reactant molecules called substrates. Enzymes are incredibly efficient catalysts and work at relatively low temperatures, doing what?

Answer 37

Enzymes: 1. Are incredibly efficient catalysts 2. Work at relatively low temperatures ,conserving energy in the biotechnology industry

Question 38

Catalysts are often very expensive precious metals. | Gold, platinum and palladium are all costly, but are what?

Answer 38

1. Gold 2. Platinum 2. Palladium are all costly, but are the most effective catalysts for particular reactions

Question 39

Catalysts are often very expensive precious metals. Gold, platinum and palladium are all costly, but are the most effective catalysts for particular reactions. It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because what?

Answer 39

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because to get the same rate of reaction without a catalyst would require higher: 1. Temperatures and/Or, 2. Pressures

Question 40

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because to get the same rate of reaction without a catalyst would require higher temperatures and/or pressures. So catalysts save money and help the environment, because what?

Answer 40

So catalysts save money and help the environment, because using high: 1. Temperatures 2. Pressures often involve burning fossil fuels

Question 41

It is usually cheaper to use a catalyst than to pay for the extra energy needed without one, because to get the same rate of reaction without a catalyst would require higher temperatures and/or pressures. So catalysts save money and help the environment, because using high temperatures and pressures often involve burning fossil fuels. Operating at lower temperatures and pressures conserves these non-renewable resources and stops more carbon dioxide entering the atmosphere when they are burnt, helping to do what?

Answer 41

Operating at lower temperatures and pressures: 1. Conserves these non-renewable resources 2. Stops more carbon dioxide entering the atmosphere when they are burnt, helping to combat climate change

Question 42

Not only does a catalyst speed up a reaction, but it also does not get used up in the reaction, so what?

Answer 42

Not only does a catalyst speed up a reaction, but it also does not get used up in the reaction, so a tiny amount of catalyst can be used to speed up a reaction: 1. Over 2. Over again

Question 43

Not only does a catalyst speed up a reaction, but it also does not get used up in the reaction, so a tiny amount of catalyst can be used to speed up a reaction over and over again. However, the catalysts used in chemical plants eventually become 'poisoned,' so that they what?

Answer 43

The catalysts used in chemical plants eventually become 'poisoned,' so that they do not work anymore