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gcse science C4 - C

specific for ocr gateway additonal science B.

QuestionAnswer
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
Created by: jirwin
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