To meet the global challenge of food security, the chemical industry has continually improved agricultural processes and products. Synthetic nitrogenous fertilizers are designed to deliver nitrogen—the primary macronutrient for leaf growth—in highly concentrated, stable forms.
Two common synthetic fertilizers used globally are urea, CO(NH2)2\text{CO(NH}_2)_2CO(NH2)2, and ammonium nitrate, NH4NO3\text{NH}_4\text{NO}_3NH4NO3.
What is the percentage by mass of nitrogen in pure urea and pure ammonium nitrate respectively? (Use Ar A_r\,Ar values: H=1.0\text{H} = 1.0H=1.0, C=12.0\text{C} = 12.0C=12.0, N=14.0\text{N} = 14.0N=14.0, O=16.0\text{O} = 16.0O=16.0)
46.7%46.7\%46.7% and 35.0%35.0\%35.0%
23.3%23.3\%23.3% and 17.5%17.5\%17.5%
35.0%35.0\%35.0% and 46.7%46.7\%46.7%
46.7%46.7\%46.7% and 17.5%17.5\%17.5%
81 exam-style questions on OCR GCSE Chemistry Improving processes and products. Each one has a worked solution and a mark scheme showing where the marks go.