0620_w18_qp_42
A paper of Chemistry, 0620
Questions:
5
Year:
2018
Paper:
4
Variant:
2
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1
ElementX can undergo the following physical changes. gaseous X boiling or evaporation liquid X solid X Give the scientific name for each of the numbered physical changes.  Explain why the changes shown are physical changes. One difference between boiling and evaporation is the rate at which the processes occur. State one other difference between boiling and evaporation. Describe the separation, arrangement and motion of particles of elementX in the solid state. separation arrangement motion  ElementX is a GroupI metal. It burns in air to form an oxide X2O. Write a chemical equation for this reaction. 
1. States of matter  →  1.1. Solids, liquids and gases
6. Chemical reactions  →  6.1. Physical and chemical changes
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2
Magnesium, calcium and strontium are GroupII elements. Complete the table to show the arrangement of electrons in a calcium atom. shell number number of electrons  Describe how the arrangement of electrons in a strontium atom is: similar to the arrangement of electrons in a calcium atom different from the arrangement of electrons in a calcium atom.  Calcium reacts with cold water to form two products: ● ● a colourless gas, P, which ‘pops’ with a lighted splint ● ● a weakly alkaline solution, Q, which turns milky when carbondioxide is bubbled through it. Name gas P. Identify the ion responsible for making solution Q alkaline. Suggest the pH of solutionQ. Write a chemical equation for the reaction of calcium with cold water. Magnesium reacts with chlorine to form magnesiumchloride, MgCl 2. Magnesiumchloride is an ionic compound. Complete the diagrams to show the electronic structures of the ions in magnesiumchloride. Show the charges on the ions. Cl Mg Cl  Give three physical properties that are typical of ionic compounds such as MgCl 2.  Aqueous magnesiumchloride is added to aqueous silvernitrate. A white precipitate forms. Write an ionic equation for this reaction. Include state symbols. 
9. Metals  →  9.4. Reactivity series
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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3
Sulfur is an important element. Explain how burning fossil fuels containing sulfur leads to the formation of acid rain. Sulfuricacid is manufactured by the Contact process. One step in the Contact process involves a reversible reaction in which sulfur trioxide, SO3, is formed. Write a chemical equation for this reversible reaction. Include the correct symbol to show that the reaction is reversible. State the conditions and name the catalyst used in this reversible reaction. temperature pressure catalyst  Describe how the sulfurtrioxide formed is converted into sulfuricacid in the next steps of the Contact process. Dilute sulfuricacid is used to make salts known as sulfates. A method consisting of three steps is used to make zincsulfate from zinccarbonate. step 1 Add an excess of zinccarbonate to 20 cm3 of 0.4 mol / dm3 dilute sulfuricacid until the reaction is complete. step 2 Filter the mixture. step 3 Heat the filtrate until a saturated solution forms and then allow it to crystallise. Name a suitable piece of apparatus for measuring 20 cm3 of dilute sulfuricacid in step1. State two observations which would show that the reaction is complete in step1.  Why is it important to add an excess of zinccarbonate in step1? What is meant by the term saturated solution in step3? The equation for the reaction is shown. ZnCO3+ H2SO4ZnSO4( ) + H2O+ CO2Complete the equation by inserting the state symbol for zincsulfate. Name another zinc compound which could be used to make zinc sulfate from dilute sulfuricacid using this method. Suggest why this method would not work to make bariumsulfate from bariumcarbonate and dilute sulfuricacid. In a titration, a student added 25.0 cm3 of 0.200 mol / dm3 aqueous sodium hydroxide to a conicalflask. The student then added a few drops of methylorange to the solution in the conicalflask. Dilute sulfuricacid was then added from a burette to the conical flask. The volume of dilute sulfuricacid needed to neutralise the aqueous sodiumhydroxide was 20.0 cm3. 2NaOH + H2SO4 Na2SO4 + 2H2O What was the colour of the methyl orange in the aqueous sodiumhydroxide? Determine the concentration of the dilute sulfuricacid in g / dm3. ● Calculate the number of moles of aqueous sodiumhydroxide added to the conical flask.  mol ● Calculate the number of moles of dilute sulfuricacid added from the burette.  mol ● Calculate the concentration of the dilute sulfuricacid in mol / dm3.  mol / dm3 ● Calculate the concentration of the dilute sulfuricacid in g / dm3.  g / dm3  Iron(sulfate decomposes when heated strongly. 2FeSO4Fe2O3+ SO2+ SO315.20 g of FeSO4was heated and formed 4.80 g of Fe2O3. [Mr, FeSO4 = 152; Mr, Fe2O3 = 160] Calculate the percentage yield for this reaction.  % 
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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4
A student investigated the progress of the reaction between dilute hydrochloricacid, HCl, and an excess of large pieces of marble, CaCO3, using the apparatus shown. gas syringe dilute hydrochloric acid an excess of large pieces of marble A graph of the volume of gas produced against time is shown. volume of gas produced / cm3 time / s How does the shape of the graph show that the rate of reaction decreased as the reaction progressed? Why did the rate of reaction decrease as the reaction progressed? After how many seconds did the reaction finish?  s The experiment was repeated using the same mass of smaller pieces of marble. All other conditions were kept the same. Draw a graph on the grid to show the progress of the reaction using the smaller pieces of marble. The original experiment was repeated at a higher temperature. All other conditions were kept the same. Describe and explain, in terms of collisions between particles, the effect of using a higher temperature on the time taken for the reaction to finish. 
6. Chemical reactions  →  6.2. Rate of reaction
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5
Alkynes are a homologous series of unsaturated hydrocarbons. All members contain a C≡C triple bond. Complete the table showing information about the first three alkynes. formula C2H2 C3H4 structure H–C≡C–H H–C≡C–CH3 H–C≡C–CH2–CH3 name ethyne butyne  Complete the dot-and-cross diagram to show the electron arrangement in a molecule of ethyne, H–C≡C–H. Show outer shell electrons only. H H C C  Compounds in the same homologous series have the same general formula. Give two other characteristics of members of a homologous series.  Use the information in the table in to deduce the general formula of alkynes. Alkynes are unsaturated. Describe a test for unsaturation. test result  Name an oxidising agent which can be used to oxidise ethanol to ethanoic acid. Draw the structure of ethanoicacid. Show all of the atoms and all of the bonds.  Carboxylic acids can be converted into esters. The ester formed by reacting propanoic acid and methanol has the molecular formula C4H8O2. Name this ester and draw its structure. Show all of the atoms and all of the bonds. name of the ester structure of the ester  Name another ester with the molecular formula C4H8O2. Polyesters are polymers. What type of polymerisation is used in the manufacture of polyesters? Name a polyester. 
11. Organic chemistry  →  11.1. Formulae, functional groups and terminology
11. Organic chemistry  →  11.2. Naming organic compounds
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