NPK Fertilisers - P-containing Compound
Chemistry: AQA GCSE Higher, topic 10.4.8
Phosphorus-Containing Compounds in Fertilisers
Phosphate rock is a source of insoluble phosphorus that is obtained by mining. Useful soluble products can be obtained by treating the rock with acids:
Phosphate rock + nitric acid
- Phosphate rock + nitric acid → phosphoric acid + calcium nitrate
Phosphate rock + sulfuric acid
- Phosphate rock + sulfuric acid → single superphosphate
- Single superphosphate is a mixture of calcium sulfate and calcium phosphate.
Phosphate rock + phosphoric acid
- Phosphate rock + phosphoric acid → triple superphosphate
- Triple superphosphate is also known as calcium phosphate.
Test yourself on NPK Fertilisers - P-containing Compound
Why is phosphate rock treated with acids before it is used in fertilisers?
Triple superphosphate, made from phosphate rock and phosphoric acid, is a single calcium compound. Single superphosphate, made from phosphate rock and sulfuric acid, is a mixture of two calcium compounds. Name these two compounds.
How does the reaction between phosphate rock and nitric acid differ from the reaction between phosphate rock and sulfuric acid?
How does the composition of single superphosphate differ from the composition of triple superphosphate?
Phosphate rock reacts with nitric acid to produce phosphoric acid and calcium nitrate. If this phosphoric acid is then reacted with more phosphate rock, what product forms?