C3.4 Gases, equilibria and ammonia

Question 1

How many particles does one mole of any substance contain?

Answer 1

6.02 x 10^23 particles

Question 2

How can you work out the number of moles of any substance?

Answer 2

Number of moles = mass in grams / relative atomic or formula mass

Question 3

What is normal atmospheric pressure equal to?

Answer 3

1 atmosphere

Question 4

What is stated in Avogadro’s law?

Answer 4

1 mole of any gas at room temperature and normal atmospheric pressure has a volume of 24dm^3

Question 5

What is the room temperature used in Avogadro’s law equal to?

Answer 5

25 C

Question 6

What do fertilisers contain that plants need to make proteins?

Answer 6

Soluble nitrogen compounds

Question 7

Why are fertilisers added to soil?

Answer 7

To promote growth in plants

Question 8

What does the Haber process produce?

Answer 8

Ammonia

Question 9

What is the reaction for the production of ammonia?

Answer 9

Nitrogen + hydrogen ammonia

Question 10

Where is nitrogen obtained from when obtaining ammonia for nitrogenous fertilisers?

Answer 10

The air

Question 11

Where is hydrogen obtained from when obtaining ammonia for nitrogenous fertilisers?

Answer 11

Natural gas

Question 12

What does it mean when a reaction is reversible?

Answer 12

It happens in both the forwards and backwards reactions

Question 13

What gas is natural gas mainly composed of?

Answer 13

Methane

Question 14

What is an advantage of artificial fertilisers?

Answer 14

More crops can be grown so more people can be fed

Question 15

What is the disadvantage of artificial fertilisers?

Answer 15

They can easily be washed out of soil and into rivers and lakes, which can cause eutrophication

Question 16

Why are artificial fertilisers easily washed out of soil?

Answer 16

They’re highly soluble

Question 17

What is eutrophication?

Answer 17

The build up of nitrates and phosphates in water which encourages excessive plant and algae growth, leading to a depletion of light and oxygen supplies, which leads to other organisms in the water dying off

Question 18

What happens during an exothermic reaction?

Answer 18

Heat is released because more energy is needed to make bonds than to break them

Question 19

Is bond-making an exothermic or endothermic process?

Answer 19

Exothermic

Question 20

Is bond-breaking an exothermic or endothermic process?

Answer 20

Endothermic

Question 21

What happens during an endothermic reaction?

Answer 21

Heat is taken in because more energy is needed to break bonds than to make them

Question 22

What is dynamic equilibrium?

Answer 22

When the forwards and backwards reactions happen at the same rate

Question 23

What happens if a reaction in equilibrium is subject to a change in conditions?

Answer 23

It will adjust to cancel out the change

Question 24

What conditions are used during the Haber process?

Answer 24

• temperature of 450 degrees
• pressure of 200 atmospheres
• presence of an iron catalyst

Question 25

What happens when equilibrium shifts to the right?

Answer 25

More product is produced

Question 26

Why is a high temperature used during the Haber process even though it shifts equilibrium to the left?

Answer 26

Because if it didn’t the reaction would be very slow