A research laboratory uses nitrogen dioxide, NO2\mathrm{NO_2}NO2, in a sealed reaction chamber.
Relative atomic mass (ArA_rAr): N = 14.0 O = 16.0
The Avogadro constant is 6.02 × 1023.
How many grams of nitrogen dioxide contain a total of 9.03 × 1022 atoms?
2.30 g2.30\,\text{g}2.30g
20.7 g20.7\,\text{g}20.7g
6.90 g6.90\,\text{g}6.90g
1.50 g1.50\,\text{g}1.50g
134 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.