A technician is checking molecular formulae entered in a laboratory database.
| Substance | Molecular formula |
|---|---|
| ethene | C2H4\mathrm{C_{2}H_{4}}C2H4 |
| propene | C3H6\mathrm{C_{3}H_{6}}C3H6 |
| glucose | C6H12O6\mathrm{C_{6}H_{12}O_{6}}C6H12O6 |
| carbon dioxide | CO2\mathrm{CO_{2}}CO2 |
Name the pair whose formulae simplify to the same ratio of atoms.
Write the empirical formula shared by this pair.
Write the simplest whole-number ratio of atoms in glucose. Label the elements in your ratio.
Relative atomic masses (ArA_rAr): C = 12.0, O = 16.0
Calculate Mr M_r\,Mr for the carbon dioxide entry.
A reaction record contains this balanced equation.
2Mg+O2→2MgO \mathrm{2Mg + O_{2} \rightarrow 2MgO} 2Mg+O2→2MgORelative atomic masses (ArA_rAr): Mg = 24.3, O = 16.0
Show, using calculations, that the total relative formula mass is equal on the two sides of the equation.
102 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.