9.4. Reactivity series
A subsection of Chemistry, 0620, through 9. Metals
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This question is about sulfuricacid and salts that are made from sulfuricacid. Zinc reacts with dilute sulfuricacid. Aqueous zincsulfate is one of the products. Powdered zinc is added to dilute sulfuricacid. The mixture is stirred. More zinc is added, with stirring, until the zinc is in excess. Zn+ H2SO4→ ZnSO4+ H2The mixture is then filtered. Name the limiting reactant. State two observations that indicate the zinc is in excess.  Name the filtrate. Name two compounds which both react with dilute sulfuric acid to produce aqueous zincsulfate.  Zincsulfate crystals are produced by heating aqueous zincsulfate until a saturated solution is formed. When the saturated solution cools down, crystals of zincsulfate start to form. State what is meant by the term saturated solution. Explain why crystals form when the saturated solution cools down. Nickel(sulfate crystals contain water of crystallisation. When nickel(sulfate crystals, NiSO4•xH2O, are heated, they give off water. NiSO4•xH2O→ NiSO4+ xH2OA student carries out an experiment to determine the value of x in NiSO4•xH2O. step 1 Nickel(sulfate crystals are weighed. step 2 Nickel(sulfate crystals are heated. step 3 The remaining solid is allowed to cool and is then weighed. step 4 The remaining solid is heated again, allowed to cool and is then weighed. step 5 Step4 is repeated until there is no change in mass. State the term used to describe crystals that contain water of crystallisation. State why step4 is repeated until there is no change in mass. In an experiment, 0.454 g of nickel(sulfate crystals, NiSO4•xH2O, is used. The mass of anhydrous nickel(sulfate, NiSO4, remaining is 0.310 g. [Mr: NiSO4, 155; H2O, 18] Determine the value of x in NiSO4•xH2O. Use the following steps. ● Calculate the number of moles of NiSO4 remaining.  moles of NiSO4 = ● Calculate the mass of H2O given off.  mass of H2O = g ● Calculate the number of moles of H2O given off.  moles of H2O =
0620_w23_qp_43
THEORY
2023
Paper 4, Variant 3
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