Chemistry 2022 Oct/Nov Paper 33 | Past Paper

Q1

Short Answer 1 mark

An iron compound can contain Fe ions, Fe ions or both ions. In this experiment, you will determine the percentage by mass of iron in FA 1, an unknown compound. You will first prepare a solution of the compound and then carry out a titration using acidified potassium manganate( VII), KMnO5Fe

Q1(aq)

Short Answer 1 mark

+ MnO

Q1(aq)

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+ 4H O

Q1(aq)(l)

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The end-point of the titration is when all the Fe ions have been oxidised and so unreacted potassium manganate( VII) causes the colour of the solution to become a permanent pale pink. FA 1 is a sample of the unknown compound. potassium manganate( VII), KMnO FA 3 is dilute sulfuric acid, H

Q1(a)

Structured 8 marks

Method Weighing the compound beaker. Preparing the solution of distilled water to the beaker and stir until the FA 1 has dissolved. volumetric flask. flask. Titration of FA 4 into a conical flask. of FA 3 to the conical flask. rough titre = cm results. of FA 2 added in each accurate titration.

Q1(b)

Short Answer 1 mark

From your accurate titration results, calculate a suitable mean value to use in your calculations. Show clearly how you obtained this value. of FA 4 required cm of FA 2. [1]IIIVII VIII

Q1(c)

Short Answer 1 mark

Calculations

Q1(i)

Short Answer 1 mark

Give your answers to (c)(ii), (c)(iii) and (c)(iv) to the appropriate number of significant figures.

Q1(ii)

Short Answer 1 mark

Calculate the amount, in mol, of manganate( VII) ions in the volume recorded in

Q1(ii)(b)

Short Answer 1 mark

. amount of MnO = mol

Q1(iii)

Short Answer 1 mark

Calculate the amount, in mol, of iron( II) ions in the weighed sample of FA 1. amount of Fe = mol

Q1(iv)

Short Answer 2 marks

Calculate the percentage by mass of iron in FA 1. Show your working. percentage by mass of iron = %

Q1(d)

Short Answer 1 mark

A student carries out the same experiment as in

Q1(d)(a)

Short Answer 1 mark

. The student receives a sample of FA 1 in a container with a lid. The student records the initial mass of the container with its lid and the sample of FA 1. Then the student records the mass of the container with the residue but forgets to replace the lid. How would this error alter the student's answer to

Q1(e)

Short Answer 1 mark

State two assumptions that have been made in calculating the percentage by mass of iron in FA 1 in (c)(iv). [Total: 17] Question 2 starts on the next page.

Q2

Short Answer 1 mark

In this experiment you will determine the percentage by mass of magnesium in a hydrated salt, O, where X represents the anion. You will measure the loss of mass when a sample of the hydrated salt is heated to form the anhydrous salt.

Q2(a)

Structured 5 marks

Method While the crucible is cooling you may wish to begin work on Question 3. Record the mass.

Q2(b)

Short Answer 1 mark

Calculations

Q2(i)

Short Answer 1 mark

Calculate the amount, in mol, of water lost. amount of H O lost = mol [1]III

Q2(ii)

Short Answer 2 marks

Calculate the percentage by mass of magnesium in FA 5. Show your working. percentage by mass of Mg = %

Q2(c)

Short Answer 1 mark

Suggest two assumptions that must be made for this experiment to give an accurate value of the percentage of Mg. [Total: 10] Qualitative analysis For each test you should record all your observations in the spaces provided. Examples of observations include: added You should record clearly at what stage in a test an observation is made. Where no change is observed you should write 'no change'. Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given. If any solution is warmed, a boiling tube must be used. Rinse and reuse test-tubes and boiling tubes where possible. No additional tests should be attempted.

Q3(a)

Short Answer 1 mark

FA 6 is an acidified aqueous solution of a salt which contains two cations and one anion, all of which are listed in the Qualitative analysis notes.

Q3(i)

Short Answer 2 marks

Select a reagent or reagents for use in tests to identify the two cations. Record your observations.

Q3(ii)

Short Answer 2 marks

The anion in FA 6 is either the sulfate ion, SO , or the sulfite ion, SO Select a reagent or reagents for use in tests to identify the anion. Record your observations.

Q3(iii)

Short Answer 2 marks

Identify the ions present in FA 6 and give their formulae. The cations present in FA 6 are and . The anion present in FA 6 is .

Q3(b)

Short Answer 2 marks

Carry out the tests and record your observations. test observations Test 1 sodium sulfite, then Rinse out this test-tube thoroughly. Test 2 potassium iodide, then add a few drops of starch solution.

Q3(c)

Short Answer 1 mark

FA 7, FA 8 and FA 9 are aqueous solutions of sodium salts. Each solution contains one of the following ions: CO You will identify which solution contains which ion.

Q3(i)

Short Answer 3 marks

Carry out the tests and record your observations. test observations FA 7 FA 8 FA 9 Add a few drops of aqueous silver nitrate, then add aqueous ammonia.

Q3(ii)

Short Answer 1 mark

If your results are insufficient to identify which anion is present in each solution, carry out a further test. Record your test and observations.

Q3(iii)

Short Answer 1 mark

Identify which solution contains which ion. The CO ion is present in . ion is present in . ion is present in . [1] [Total: 13] Qualitative analysis notes 1 Reactions of cations cation reaction with NaOH(aq) NH

Q3(aq)

Short Answer 1 mark

aluminium, Al

Q3(aq)

Short Answer 1 mark

white ppt. soluble in excess white ppt. insoluble in excess ammonium, NH

Q3(aq)

Short Answer 1 mark

no ppt. ammonia produced on warming barium, Ba

Q3(aq)

Short Answer 1 mark

faint white ppt. is observed unless [Ba

Q3(aq)

Short Answer 1 mark

] is very low no ppt. calcium, Ca

Q3(aq)

Short Answer 1 mark

white ppt. unless [Ca

Q3(aq)

Short Answer 1 mark

] is verylow no ppt. chromium( III), Cr

Q3(aq)

Short Answer 1 mark

grey-green ppt. soluble in excess giving dark green solution grey-green ppt. insoluble in excess copper( II), Cu

Q3(aq)

Short Answer 1 mark

pale blue ppt. insoluble in excesspale blue ppt. soluble in excess giving dark blue solution iron( II), Fe

Q3(aq)

Short Answer 1 mark

green ppt. turning brown on contact with air insoluble in excess green ppt. turning brown on contact with air insoluble in excess iron( III), Fe

Q3(aq)

Short Answer 1 mark

red-brown ppt. insoluble in excessred-brown ppt. insoluble in excess magnesium, Mg

Q3(aq)

Short Answer 1 mark

white ppt. insoluble in excesswhite ppt. insoluble in excess manganese( II), Mn

Q3(aq)

Short Answer 1 mark

R?ZKLWHSSWUDSLGO\WXUQLQJEURZQ on contact with air insoluble in excess R?ZKLWHSSWUDSLGO\WXUQLQJEURZQ on contact with air insoluble in excess zinc, Zn

Q3(aq)

Short Answer 1 mark

white ppt. soluble in excess white ppt. soluble in excess 2 Reactions of anions anion reaction carbonate, CO liberated by dilute acids chloride, Cl

Q3(aq)

Short Answer 1 mark

gives white ppt. with Ag

Q3(aq)

Short Answer 1 mark

(soluble in NH

Q3(aq)

Short Answer 1 mark

) bromide, Br

Q3(aq)

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(partially soluble in NH

Q3(aq)

Short Answer 1 mark

) iodide, I

Q3(aq)

Short Answer 1 mark

gives pale yellow ppt. with Ag

Q3(aq)

Short Answer 1 mark

(insoluble in NH

Q3(aq)

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) nitrate, NO

Q3(aq)

Short Answer 1 mark

NH liberated on heating with OH

Q3(aq)

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and Al foil nitrite, NO

Q3(aq)

Short Answer 1 mark

NH liberated on heating with OH

Q3(aq)

Short Answer 1 mark

and Al foil; GHFRORXULVHVDFLGL?HGDTXHRXV.0Q2 sulfate, SO

Q3(aq)

Short Answer 1 mark

gives white ppt. with Ba

Q3(aq)

Short Answer 1 mark

(insoluble in excess dilute strong acids); gives white ppt. with high [Ca

Q3(aq)

Short Answer 1 mark

] VXO?WHSO

Q3(aq)

Short Answer 1 mark

gives white ppt. with Ba

Q3(aq)

Short Answer 1 mark

(soluble in excess dilute strong acids); GHFRORXULVHVDFLGL?HGDTXHRXV.0Q2 thiosulfate, S 3 Tests for gases gas test and test result ammonia, NH turns damp red litmus paper blue carbon dioxide, CO gives a white ppt. with limewater hydrogen, H ?pops? with a lighted splint oxygen, O relights a glowing splint

Q4

Short Answer 1 mark

Tests for elements element test and test result iodine, I gives blue-black colour on addition of starch solution Important values, constants and standards Faraday constant F = 9.65 u 10 Avogadro constant L = 6.022 u 10 electronic charge e = ?1.60 u 10?19 molar volume of gas V at room conditions ionic product of water K = 1.00 u 10?14 Group The Periodic Table of Elements hydrogen 1.0 He helium 4.0 12131415161718 34567891011123Li lithium 6.9 beryllium 9.0 atomic number atomic symbolKey name relative atomic mass sodium 23.0 magnesium 24.3 potassium 39.1 calcium 40.1 rubidium 85.5 strontiu m 87.6 caesium 132. 9 barium 137.3 francium Ra radium boron10.8 13 Al aluminium 27.0 31 Ga gallium 69.7 49 In indium 114.8 thallium 204.4 carbon 12.0 14 Si silicon 28.1 32 Ge germanium 72.6 50 Sntin 118.7 82 Pb lead 207.2 titanium 47.9 40 Zr zirconium 91.2 72 Hf hafnium178. 5 rutherfordium vanadium 50.9 41 Nb niobium 92.9 73 Ta tantalum 180.9 105 Db dubnium chromium 52.0 42 Mo molybdenum 95.9 74 W tungste n 183.8 106 Sg seaborgium manganese 54.9 43 Tc technetium rhenium 186. 2 107 Bh bohrium iron 55.8 44 Ru ruthenium 101.1 76 Os osmium 190.2 108 Hs hassium Co cobalt 58.9 45 Rh rhodium 102.9 iridium192.2 109 Mt meitnerium nicke l58.7 46 Pd palladium 106. 4 platinum 195. 1 110 Ds darmstadtium copper 63.5 47 Ag silver 107. 9 79 Au gold 197. 0 111 Rg roentgenium zinc 65.4 48 Cd cadmium 112.4 80 Hg mercury 200. 6 112 Cn copernicium flerovium livermorium nitrogen 14.0 phosphorus 31.0 33 As arsenic 74.9 51 Sb antimony 121.8 bismuth 209.0 oxygen 16.0 sulfur 32.1 34 Se selenium 79.0 52 Te tellurium 127.6 84 Po polonium fluorine 19.0 17 Cl chlorine 35.5 35 Br bromine 79.9 iodine 126.9 Ne neon 20.2 18 Ar argo n39.9 krypto n 83.8 54 Xe xenon131. 3 86 Rn radon nihonium moscovium tennessine oganesson scandium 45.0 yttriu m 88.9 57?71 lanthanoids 89?103 actinoids 57La lanthanum 138.9 89 Ac lanthanoids actinoids actinium Ce cerium 140.1 90 Th thoriu m232.0 praseodymium 140.9 91 Pa protactinium 231.0 neodymium 144.4 uranium 238.0 promethium neptunium samarium 150.4 94 Pu plutonium europium 152.0 95 Am americium gadolinium 157.3 96 Cm curium terbiu m158.9 97 Bk berkelium dysprosium 162. 5 californium holmium 164. 9 99 Es einsteinium erbium 167. 3 100 Fm fermium Tm thulium168. 9 101 Md mendelevium ytterbiu m 173. 1 102 No nobelium lutetium 175.0 lawrencium To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series.

Board	CAIE
Level	A Level
Subject	Chemistry
Code	`9701`
Year	2022
Session	Oct/Nov
Paper No.	Paper 33
Q&A	62 questions

Chemistry 2022 · Oct/Nov · Paper 33

Questions & Model Answers 62 Qs

Paper Details