9. Metals
A section of Chemistry, 0620
Listing 10 of 1272 questions
Iron is manufactured in a blast furnace. Three of the starting materials added to the blast furnace are coke, iron ore and limestone. Name the other starting material added to the blast furnace. The source of iron in the blast furnace is Fe2O3. Fe2O3 is found in iron ore. Name the main ore of iron which contains Fe2O3. The iron in Fe2O3 is reduced by reaction with carbonmonoxide. The unbalanced symbol equation is shown. Complete the equation. Fe2O3 + CO → CO2 + Fe State the change in oxidation number of iron in the reaction in . from to ������������������������������������������������������������ Explain how the change of oxidation number shows that iron has been reduced. The major impurity in iron ore is silicon(oxide. Limestone is added to the blast furnace to remove this impurity. Write two symbol equations to show how silicon(oxide is removed. For each equation, state the type of chemical reaction that takes place. equation 1 type of chemical reaction equation 2 type of chemical reaction  Iron is converted to steel by mixing it with carbon and other elements. State the term given to a substance which is a mixture of a metal and other elements. Name one element, other than carbon, mixed with iron in the making of stainless steel. Preventing the rusting of steel is important. State the chemical name of rust. Steel can be coated with zinc to prevent rusting. This provides both a barrier method and sacrificial protection. State the term used for coating steel with zinc. Describe another barrier method for preventing rusting. Explain how zinc provides sacrificial protection. 
0620_w23_qp_42
THEORY
2023
Paper 4, Variant 2
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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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