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A-LevelChemistryAtoms, molecules and stoichiometry9701/12 · Oct/Nov 2020 · Q51 Mark

A white powder is known to be a mixture of magnesium oxide and aluminium oxide. 100 cm³ of 2 mol dm⁻³ NaOH(aq) is just enough to dissolve the aluminium oxide in x grams of the mixture. The reaction is shown. Al₂O₃ + 2OH¯ + 3H₂O → 2Al(OH)₄¯ 800 cm³ of 2 mol dm⁻³ HCl(aq) is just enough to dissolve all of the oxide in x grams of the mixture. The reactions are shown. Al₂O₃ + 6H⁺ → 2Al³⁺ + 3H₂O MgO + 2H⁺ → Mg²⁺ + H₂O How many moles of each oxide are present in x grams of the mixture?

A0.05 | 0.25
B0.05 | 0.50
C0.10 | 0.25
D0.10 | 0.50

✓ Correct answer

D: 0.10 | 0.50

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About this question

Topic
Atoms, molecules and stoichiometry, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source
A-Level Chemistry, Oct/Nov 2020 Paper 1 Variant 2, question 5.

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