Unit F335 - Chemistry by design - Specimen.PDF, 434KB - OCR
Unit F335 - Chemistry by design - Specimen.PDF, 434KB - OCR
Unit F335 - Chemistry by design - Specimen.PDF, 434KB - OCR
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2<br />
Answer all the questions.<br />
1 Hydrogen is used to make ammonia, an important agricultural chemical.<br />
Ammonia is used to make fertilisers.<br />
N2(g) + 3H2(g) 2NH3(g) equation 1.1<br />
(a) (i) Suggest the cheapest source for the nitrogen gas used in equation 1.1.<br />
........................................................................................................................................ [1]<br />
(ii) Ammonium nitrate, NH4NO3, is a fertiliser made from ammonia.<br />
Calculate the percentage <strong>by</strong> mass of nitrogen in NH4NO3.<br />
(iii) Ammonium sulfate is another fertiliser.<br />
Write the formula of ammonium sulfate.<br />
answer = ...................................................% [2]<br />
........................................................................................................................................ [1]<br />
(iv) Explain one advantage and one disadvantage of adding ammonium salts to the soil.<br />
.............................................................................................................................................<br />
.............................................................................................................................................<br />
.............................................................................................................................................<br />
........................................................................................................................................ [2]<br />
(b) Hydrogen is produced industrially from methane <strong>by</strong> steam reforming as shown below.<br />
CH4(g) + H2O(g) CO(g) + 3H2(g) equation 1.2<br />
(i) Write an expression for Kc for the reaction in equation 1.2.<br />
[2]
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