A laboratory technician compares the nitrogen content of two containers of pure compounds.
| Container | Compound | Formula | Mass of compound (g\mathrm{g}g) |
|---|---|---|---|
| A | calcium nitrate | Ca(NO3)2\mathrm{Ca(NO_3)_2}Ca(NO3)2 | 18.5 |
| B | ammonium phosphate | (NH4)3PO4\mathrm{(NH_4)_3PO_4}(NH4)3PO4 | 12.0 |
Relative atomic masses: H=1\mathrm{H}=1H=1, N=14\mathrm{N}=14N=14, O=16\mathrm{O}=16O=16, P=31\mathrm{P}=31P=31, Ca=40\mathrm{Ca}=40Ca=40.
Calculate the percentage by mass of nitrogen in each compound.
Use your answers to part (a) to find the mass of nitrogen in each container. State which container holds the greater mass of nitrogen, and give the difference in the mass of nitrogen between the two containers.
142 exam-style questions on Edexcel GCSE Chemistry 2.6 Calculations involving masses, covering 2.6.1 Relative formula mass and percentage composition, 2.6.2 Empirical and molecular formulae, 2.6.3 Conservation of mass, 2.6.4 Reacting masses and concentration in g dm⁻³, 2.6.5 The mole and the Avogadro constant, and 2.6.6 Limiting reactants and stoichiometry. Each one has a worked solution and a mark scheme showing where the marks go.