Define relative molecular mass. Calculate the RMM of (i) glucose, C₆H₁₂O₆ and (ii) sulphuric acid, H₂SO₄ (C = 12, H = 1, O = 16, S = 32).

1. 1 · Define in one line. RMM is the ratio of the mass of one molecule to 1/12 of the mass of one C-12 atom. It has no unit.
2. 2 · State the method. RMM = sum of (number of atoms × relative atomic mass) for every element in the formula.
3. 3 · Glucose.
   • C: 6 × 12 = 72
   • H: 12 × 1 = 12
   • O: 6 × 16 = 96
   • RMM = 72 + 12 + 96 = 180
4. 4 · Sulphuric acid.
   • H: 2 × 1 = 2
   • S: 1 × 32 = 32
   • O: 4 × 16 = 64
   • RMM = 2 + 32 + 64 = 98
5. 5 · Real-life link. Glucose (RMM 180) is the sugar in ORS packets and the fuel our cells burn for energy.
6. 6 · Close in one line. Therefore the RMM of glucose is 180 and that of sulphuric acid is 98.

Scoring tip: Show the count and the multiplication for each element. A bare final number may lose a mark.