A) 1.20 × 10²³ B) 3.01 × 10²³ C) 6.02 × 10²³ D) 1.20 × 10²⁴ Question 6 Magnesium reacts with hydrochloric acid according to the equation:
Exam Board: Cambridge CIE 0620 Paper: 2 – Multiple Choice (Extended) – Extract Topic: Stoichiometry & Mole Calculations Time allowed: 15 minutes (extract) Total marks: 10 Section A: Multiple Choice Questions Question 1 What is the mass of one mole of carbon dioxide (CO₂)? (Ar: C = 12, O = 16) igcse chemistry past paper
Which statement about the mole is correct? (Ar: Mg = 24) [2] [ \text{Mg (s)
Calculate the number of moles of magnesium in 2.4 g of Mg. (Ar: Mg = 24) [2] 1 mark for volume)
[ \text{Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g)} ]
From equation: 1 mol Mg → 1 mol H₂ So moles H₂ = 0.10 mol Volume H₂ = 0.10 × 24 = 2.4 dm³ (1 mark for mole ratio, 1 mark for volume)