0620_w20_qp_43
A paper of Chemistry, 0620
Questions:
6
Year:
2020
Paper:
4
Variant:
3

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The names of nine substances are shown. aluminium oxide ammonia carbon monoxide anhydrous cobalt(chloride hydrated copper(sulfate iron(oxide nitrogen dioxide silver steel Answer the following questions using these substances. Each substance may be used once, more than once or not at all. Name the substance that is: the main constituent of hematite ������������������������������������������������������������������������������������������ a gas produced in car engines which causes acid rain ������������������������������������������������������� an alkaline gas ��������������������������������������������������������������������������������������������������������������������� an element ��������������������������������������������������������������������������������������������������������������������������� a gas formed by the incomplete combustion of fossil fuels ������������������������������������������������� used to test for the presence of water. �������������������������������������������������������������������������������� 
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The table gives information about five particles, A, B, C, D and E. particle number of electrons number of neutrons number of protons A B C D E State the atomic number of A. State the nucleon number of B. Write the electronic structure of C. Give the letters of all the particles which are: atoms ���������������������������������������������������������������������������������������������������������������������������� positive ions ������������������������������������������������������������������������������������������������������������������ negative ions ���������������������������������������������������������������������������������������������������������������� isotopes of each other. ������������������������������������������������������������������������������������������������� 
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Zinc is manufactured from zincblende. Zincblende is an ore which consists mainly of zincsulfide, ZnS. Zincblende is roasted in air. One of the products is zincoxide. Name the other product formed in this reaction. Zincoxide is then converted into zinc. Zincoxide and coke, a source of carbon, are heated in a furnace. Hot air is blown into the furnace. Give two reasons why coke is needed.  Write a chemical equation for the formation of zinc in the furnace. Zinc has a melting point of 420 °C and a boiling point of 907 °C. The temperature inside the furnace is 1200 °C. Explain how this information shows that the zinc produced inside the furnace is a gas. The gaseous zinc is converted to molten zinc. Name this change of state. Zinc reacts with dilute sulfuricacid to produce aqueous zincsulfate. Zn+ H2SO4→ ZnSO4+ H2Hydrated zincsulfate crystals are made from aqueous zincsulfate. Step 1 Solid zinc is added to dilute sulfuricacid until zinc is in excess. Step 2 Excess zinc is separated from aqueous zincsulfate by filtration. Step 3 Aqueous zincsulfate is heated until the solution is saturated. Step 4 The saturated solution is allowed to cool and crystallise. Step 5 The crystals are removed and dried. Name the residue in step2. In step3, a saturated solution is produced. Describe what a saturated solution is. Name two compounds each of which react with dilute sulfuricacid to produce aqueous zincsulfate.  When hydrated magnesiumsulfate crystals, MgSO4•xH2O, are heated they give off water. MgSO4•xH2O→ MgSO4+ xH2OA student carries out an experiment to determine the value of x in MgSO4•xH2O. Step 1 Hydrated magnesiumsulfate crystals were weighed. Step 2 Hydrated magnesiumsulfate crystals were heated. Step 3 The remaining solid was weighed. Describe how the student can ensure that all the water is given off. In an experiment, all the water was removed from 1.23 g of MgSO4•xH2O. The mass of MgSO4 remaining was 0.60 g. Mr: MgSO4 = 120; Mr: H2O = 18 Determine the value of x using the following steps. ● Calculate the number of moles of MgSO4 remaining.  moles of MgSO4 = ● Calculate the mass of H2O given off.  mass of H2O = g ● Calculate the moles of H2O given off.  moles of H2O = ● Determine the value of x.  x =  
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