3.2. Relative masses of atoms and molecules
A subsection of Chemistry, 5070, through 3. Stoichiometry
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This question is about the chlorides of the elements in Period 3. State the electronic configuration of the positive ion in sodium chloride, NaCl. Magnesium chloride crystals can be prepared by reacting an insoluble base with an acid. Name an insoluble base and the acid that can be used. insoluble base acid Describe the essential practical details for the preparation of pure magnesium chloride crystals. Anhydrous aluminium chloride contains 20.2% by mass of aluminium. Show that the empirical formula for anhydrous aluminium chloride is Al Cl 3. A sample of anhydrous aluminium chloride has a mass of 2.34 g. The sample contains 0.00876 mol of anhydrous aluminium chloride. Calculate the relative molecular mass and give the molecular formula for anhydrous aluminium chloride. relative molecular mass molecular formula Silicon(chloride, SiCl4, has a simple molecular structure. Predict one physical property of silicon(chloride at room temperature.
5070_s20_qp_21
THEORY
2020
Paper 2, Variant 1
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This question is about some of the oxides of the elements in Period 3. State the electronic configuration of the negative ion in sodium oxide, Na2O. Magnesium oxide is an insoluble base that can be used to prepare pure magnesium sulfate crystals. Describe the essential practical details for the preparation of pure magnesium sulfate crystals from magnesium oxide. An oxide of phosphorus contains 43.7% by mass of phosphorus. Show that the empirical formula for this oxide is P2O5. A sample of this oxide has a mass of 2.56 g. The sample contains 0.00901 mol of the oxide. Calculate the relative molecular mass and hence the molecular formula for this oxide of phosphorus. relative molecular mass molecular formula State the structure and bonding in silicon dioxide, SiO2.
5070_s20_qp_22
THEORY
2020
Paper 2, Variant 2
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