c2 - Fertilisers & Crop yield, Chemicals from the sea Flashcards
What are fertilisers?
Chemicals that give plants essential chemical elements for growth
What do fertilisers do for plants?
They make crops grow faster and bigger, and increase the crop yield
How do fertilisers increase crop yield?
They replace essential elements in the soil that have been used up by previous crops, and provide nitrogen as soluble nitrates which are used by the plant to make protein for growth
What are the three main essential elements found in fertilisers?
nitrogen (N), phosphorus (P) and potassium (K)
Which three pieces of apparatus do you need to be able to label?
burette, measuring cylinder and filter funnel
How do you make ammonium sulfate?
Neutralise sulfuric acid with ammonia
How do you make ammonium nitrate?
Neutralise nitric acid with ammonia
How do you make ammonium phosphate?
Neutralise phosphoric acid with ammonia
How do you make potassium nitrate?
Neutralise nitric acid with potassium hydroxide
What is eutrophication?
When the overuse of fertilisers changes the ecosystem in lakes, rivers and streams
What are the three stages of eutrophication?
1) Fertilisers used by farmers may be washed into lakes and rivers. This increases the levels of nitrates and phosphates in the water and more simple algae grow.
2) The algal bloom blocks off sunlight to other plants, causing them to die and rot
3) Aerobic bacteria feed of the dead organisms and increase in number. They quickly use up the oxygen until nearly all the oxygen is removed. There isn’t enough oxygen left to support the larger organisms, such as fish and other aquatic animals, so they suffocate
As well as a food preservative and flavouring, what is sodium chloride useful as?
A raw material in the chemical industry.
Why is sodium chloride useful as a raw material in the chemical industry?
Because it is an important source of chlorine and sodium hydroxide
Where is sodium chloride mined mostly in the UK?
In Cheshire
What does rock salt mining cause in some parts of Cheshire?
Subsidence
When concentrated sodium chloride solution is electrolysed, what must the electrodes be made from and why?
Inert materials because the materials are very reactive
When concentrated sodium chloride solution is electrolysed, which electrode does the the hydrogen go to?
The cathode (negative electrode)
When concentrated sodium chloride solution is electrolysed, which electrode does the the chlorine go to?
The anode (positive electrode)
How do you test for chlorine?
With damp litmus paper, if it’s bleached, chlorine is present
Give one use of sodium hydroxide
Making soap
Give one use of hydrogen
Making margarine
Give two uses of chlorine
Sterilising water & making solvents and plastics
What is sodium hydroxide reacted with chlorine to make?
Household bleach
Describe the experimental method used to make potassium sulfate solution.
Titration is when an alkali is added to an acid until it is neutralised or vice versa
