0620_w18_qp_43
A paper of Chemistry, 0620
Questions:
6
Year:
2018
Paper:
4
Variant:
3
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1
Answer the following questions using only the substances in the list. Each substance may be used once, more than once or not at all. ammonia bauxite carbon dioxide carbon monoxide hematite oxygen sodium chloride sulfur dioxide State which substance is: an element an ore of iron used to bleach wood pulp used to manufacture fertilisers a toxic gas produced during the incomplete combustion of hydrocarbons an ionic compound a reactant in photosynthesis a product of photosynthesis.
10. Chemistry of the environment  →  10.3. Air quality and climate
10. Chemistry of the environment  →  10.1. Water
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2
This question is about electrolysis. What is meant by the term electrolysis? Name the type of particle responsible for the conduction of electricity during electrolysis in: the metal wires the electrolyte The table gives information about the products of the electrolysis of two electrolytes. Platinum electrodes are used in each case. Give two reasons why platinum is suitable to use as an electrode.  Complete the table. electrolyte observation at the anode (+) name of product at the anode (+) observation at the cathode (–) name of product at the cathode (–) concentrated aqueous potassiumchloride bubbles of colourless gas aqueous copper(sulfate bubbles of colourless gas
4. Electrochemistry  →  4.1. Electrolysis
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3
Tin is a metallic element in Group IV. Its main ore is cassiterite which is an impure form of tin(oxide, SnO2. Tin also occurs in stannite, Cu2FeSnS4. Calculate the relative formula mass, Mr, of Cu2FeSnS4. Mr of Cu2FeSnS4 = The Mr of SnO2 is 151. Calculate the percentage of tin by mass in SnO2. percentage of tin by mass in SnO2 = The percentage of tin by mass in Cu2FeSnS4 is 27.6%. Use this information and your answer to to suggest whether it would be better to extract tin from SnO2 or Cu2FeSnS4. Explain your answer. Tin can be extracted by heating tin(oxide with carbon. Carbonmonoxide is the other product. Write a chemical equation for this reaction. The position of tin in the reactivity series is shown. iron most reactive tin copper least reactive A student added iron to a solution containing Sn2+ ions. The student then separately added tin to a solution containing Cu2+ ions. Complete the ionic equations. If there is no reaction write ‘no reaction’. Fe + Sn2+ Sn + Cu2+ Copper(nitrate, Cu(NO3)2, decomposes when it is heated. The only solid product is copper(oxide, CuO. There are two gaseous products. One of the gaseous products is oxygen. Describe a test for oxygen. test result  Name the other gaseous product. Describe its appearance. name appearance  Write a chemical equation for the thermal decomposition of copper(nitrate. Iron does not rust when it is completely coated with zinc. When the zinc is scratched, the iron still does not rust. Explain why the iron does not rust when it is completely coated with zinc. Explain why the iron still does not rust when the zinc is scratched.
9. Metals  →  9.6. Extraction of metals
9. Metals  →  9.4. Reactivity series
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4
Dilute sulfuricacid and aqueous potassiumhydroxide can be used to make potassiumsulfate crystals using a method that includes titration. conical flask dilute sulfuric acid 25.0 cm3 of aqueous potassium hydroxide A student titrated 25.0 cm3 of 0.0500 mol / dm3 aqueous potassium hydroxide with dilute sulfuric acid in the presence of an indicator. The volume of dilute sulfuric acid needed to neutralise the aqueous potassiumhydroxide was 20.0 cm3. The equation for the reaction is shown. H2SO4 + 2KOH K2SO4 + 2H2O Determine the concentration of the dilute sulfuricacid. ● Calculate the number of moles of aqueous potassium hydroxide used.  mol ● Calculate the number of moles of dilute sulfuric acid needed to neutralise the aqueous potassiumhydroxide.  mol ● Calculate the concentration of the dilute sulfuric acid.  mol / dm3 After the titration has been completed, the conical flask contains an aqueous solution of potassiumsulfate and some of the dissolved indicator. Describe how to prepare a pure, dry sample of potassiumsulfate crystals from new solutions of dilute sulfuricacid and aqueous potassiumhydroxide of the same concentrations as used in the titration. Include a series of key steps in your answer. Potassiumhydrogensulfate, KHSO4, is an acid salt. It dissolves in water to produce an aqueous solution, X, containing K+, H+ and SO4 2– ions. Describe what you would see when the following experiments are done. Magnesium ribbon is added to an excess of solutionX. A flame test is done on solutionX. An aqueous solution containing bariumions is added to solutionX. Dilute sulfuricacid reacts with bases, metals and carbonates. Write chemical equations for the reaction of dilute sulfuricacid with each of the following: magnesium hydroxide zinc sodium carbonate
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
7. Acids, bases and salts  →  7.3. Preparation of salts
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5
A student investigates the rate of reaction between lumps of calcium carbonate and dilute hydrochloricacid using the apparatus shown. CaCO3+ 2HCl CaCl 2+ CO2+ H2OThe calcium carbonate was in excess. dilute hydrochloric acid gas syringe lumps of calcium carbonate Which measurements should the student make during the reaction to determine the rate of reaction? What happens to the rate of reaction as the reaction proceeds? Explain your answer. The student repeated the experiment at a higher temperature. All other conditions were kept the same. The student found that the rate of reaction increased. Explain, in terms of collisions, why the rate of reaction increased. Apart from using a higher temperature, suggest two other methods of increasing the rate of this reaction.
6. Chemical reactions  →  6.2. Rate of reaction
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6
Ethanol can be manufactured by fermentation and by hydration. Describe these two processes of ethanol manufacture. In each case you should: ● identify the reactants ● give the reaction conditions ● write a chemical equation for the reaction which produces ethanol. fermentation hydration Give two advantages of ethanol manufacture by fermentation compared to byhydration.  State two major uses of ethanol. The structures of some polymers are shown. O O O O A C O O C O O C O O B O O C C O O O C C O O O C N H C O O N H C H N O C D CH3 CH CH2 CH3 CH CH2 CH3 CH CH2 E Answer the following questions about these polymers. Each polymer may be used once, more than once or not at all. State which polymer, A, B, C, D or E, represents: an addition polymer a protein a polyester made from only one monomer Terylene a complex carbohydrate.
11. Organic chemistry  →  11.6. Alcohols
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