3.3 Fertilisers Flashcards

1
Q

Why do we need fertilisers?

A

There are too many people to feed with too few plants if we do not fertilise the plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do plants need fertilisers?

A

Fertilisers restore nutrients (which are essential for plant growth) to the soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What three elements do fertilisers contain?

A

NPK (Nitrogen, Potassium, and Phosphorous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is ammonia needed?

A

Ammonia is the most cost effective way to obtain nitrogen for use in fertilisers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is ammonia made industrially (and what is the name of this process)?

A

The Haber process is used to produce ammonia industrially by combining nitrogen and hydrogen at a very high temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the equation for the Haber process?

A

N2 (g) + 3H2 (g) {makes a reversible reaction} 2NH3 (g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What catalyst is used in the Haber process?

A

Finely divided iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is formed when ammonia solutions react with acid?

A

A soluble ammonium salt (ammonia solution + acid —-> ammonium salt + water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Ostwald process?

A

The use of ammonia, oxygen, and water to make nitric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What catalyst is used in the Ostwald process?

A

Platinum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What property is key for fertilisers?

A

They must be soluble in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What pH is ammonia solution?

A

It is a weak alkali (pH 9)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why isn’t the temperature of the Haber process higher?

A

At higher temperatures, the reverse reaction occurs more so the overall production of ammonia becomes less eficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly