Question | Answer |
why do farmers use fertilisers? | to increase their crop yields |
how do fertilisers increase crop yield? | there's increased growth - grow bigger and faster |
what happens to the pure elements in fertilisers? | get turned into chemical compounds as the pure elements cant be put directly onto the soil |
why must fertilisers first be dissolved in water? | so they can be absorbed by plants through their roots |
what element is present in protein molecules? | nitrogen |
how do you calculate the yield when making a fertiliser? | calculate its relative formula mass |
what is an example of how to calculate yield? | ammonium nitrate, NH4N03, is 80 |
what do farmers use relative formula mass for? | to find the percentage of each element in a fertiliser and print it on the bag |
what is the equation for the percentage of an element? | percentage of element = mass of the element in the formula / relative formula mass x 100 |
what is an example of how to calculate the percentage of an element? | q. work out the percentage of nitrogen in NH4NO3
1. relative formula mass = 14 + 4 + 14 + 48 = 80
2.mass of nitrogen = 28
3.percentage of nitrogen = 28/80 x 100 = 35% |
how are fertilisers made? | neutralising alkalis with acids |
what are the 4 steps to making solid fertiliser? | 1. use a measuring cylinder to pour alkali into a conical flask.
2. use a burette to add acid to the alkali until it is neutral
3. using an evaporating basin to evaporate the solution. crystals gein to form.
4. filter off the crystals |
what is eutrophication? | the process when fertiliser dissolves in rain water and it runs into nearby water courses, such as lakes and rivers |
what is nitrogenous? | fertilisers which contain nitrogen |
what are 4 examples of fertilisers which contain nitrogen? | -ammonium nitrate
-ammonium phosphate
-ammounion sulfate
-urea |
what are 4 examples of making fertilisers? | 1. nitric acid + potassium hydroxide - potassium nitrate + water
2. nitric acid + ammonium hydroxide - ammonium nitrate
3. sulphuric acid + ammonium hydroxide - ammonium sulphate + water
4. phosphoric acid + ammonium hydroxide - ammonium phosphate + wa |