A student in Singapore heated 2.4 g of magnesium in air to form magnesium oxide. What mass of magnesium oxide was produced? [Ar: Mg = 24, O = 16] 2Mg + O₂ → 2MgO

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Question

A student in Singapore heated 2.4 g of magnesium in air to form magnesium oxide. What mass of magnesium oxide was produced? [Ar: Mg = 24, O = 16] 2Mg + O₂ → 2MgO

Accepted Answer

4.0 g — 0 g. Award 1 mark for correct calculation. Moles of Mg = 2.4/24 = 0.1 mol. From equation, 2 moles Mg produces 2 moles MgO, so 0.1 moles Mg produces 0.1 moles MgO. Mr of MgO = 24 + 16 = 40. Mass of MgO = 0.1 × 40 = 4.0 g. A is incorrect because it assumes no mass gain from oxygen. C is incorrect because it doubles the magnesium mass instead of adding oxygen mass. D is incorrect due to calculation error.

Answer

4.8 g

Answer

4.0 g

Answer

2.4 g

Answer

8.0 g

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