Chemistry 2021 Oct/Nov Paper 33 | Past Paper

Q1

Short Answer 1 mark

Group 1 metal carbonates have the formula M . The identity of the metal ion, M , may be determined by a gravimetric method. The metal carbonate is reacted with excess acid and the mass of carbon dioxide given off is measured. O(l) + CO

Q1(g)

Short Answer 1 mark

FA 1 is a Group 1 metal carbonate, M hydrochloric acid, HC l.

Q1(a)

Short Answer 1 mark

Method of FA 2 into a conical flask. Weigh the flask with the acid and record the mass. leave the flask to stand. During this step you may wish to start Question 2 or Question 3. Results [4]III

Q1(b)

Short Answer 1 mark

Calculations

Q1(i)

Short Answer 1 mark

Calculate the number of moles of carbon dioxide given off in the experiment. moles of CO = mol

Q1(ii)

Short Answer 1 mark

Calculate the relative formula mass, M , of M of M =

Q1(iii)

Short Answer 1 mark

Identify the Group 1 cation, M , in FA 1. Show your working. is .

Q1(c)

Short Answer 1 mark

One source of error in this experiment is the solubility of carbon dioxide in water.

Q1(i)

Short Answer 1 mark

Suggest one modification, to the method in

Q1(i)(a)

Short Answer 1 mark

, to reduce the solubility of carbon dioxide in the solution in the flask.

Q1(ii)

Short Answer 1 mark

An assumption made in the method in

Q1(ii)(a)

Short Answer 1 mark

is that the acid is in excess. Show by calculation that this assumption is true. [2] [Total: 10]

Q2

Short Answer 1 mark

The identity of a Group 1 metal carbonate may also be found by a titration method. in this question may or may not be the same cation as that in Question 1 . O(l) + CO

Q2(g)

Short Answer 1 mark

of a Group 1 metal carbonate, M hydrochloric acid, HC l. bromophenol blue indicator

Q2(a)

Structured 7 marks

Method of FA 3 into a conical flask. The rough titre is cm in each accurate titration.

Q2(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 3 required cm of FA 4. [1]IIIVII

Q2(c)

Short Answer 1 mark

Calculations

Q2(i)

Short Answer 1 mark

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

Q2(ii)

Short Answer 1 mark

Calculate the number of moles of hydrochloric acid present in the volume of FA 4 calculated in

Q2(ii)(b)

Short Answer 1 mark

. moles of HCl = mol

Q2(iii)

Short Answer 1 mark

Calculate the number of moles of Group 1 metal carbonate, M FA 3. moles of M = mol

Q2(iv)

Short Answer 1 mark

Calculate the relative formula mass, M , of M of M =

Q2(v)

Short Answer 1 mark

Identify the cation, M Show your working. is .

Q2(d)

Short Answer 1 mark

A student carrying out a similar experiment, using the same method, found the cation in Question 2 to be Rb . The student is told that the acid provided, FA 4, was incorrectly prepared. The cation in the student's experiment should have been identified as K Explain your answer. [1] [Total: 14] Qualitative analysis Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given. At each stage of any test you are to record details of the following: You should indicate clearly at what stage in a test a change occurs. If any solution is warmed, a boiling tube must be used. Rinse and reuse test-tubes and boiling tubes where possible. No additional tests for ions present should be attempted.

Q3(a)

Short Answer 1 mark

FA 5 is a salt containing one cation and one anion, both of which are listed in the Qualitative Analysis Notes. gently at first and then more strongly. Record all your observations. distilled water. Stir to make a solution. This solution is FA 6. You will use portions of FA 6 for the following test and tests in

Q3(a)(b)

Short Answer 1 mark

. Record your observations.

Q3(b)

Structured 4 marks

(i) FA 7 and FA 8 are solutions each containing one cation and one anion, all of which are listed in the Qualitative Analysis Notes. unless otherwise specified. observations solution FA 6 FA 7 FA 8 Add a few drops of aqueous silver nitrate. FA 6 FA 7

Q3(ii)

Structured 5 marks

Carry out tests using aqueous sodium hydroxide and dilute sulfuric acid to identify or confirm the identity of the ions in FA 6, FA 7 and FA 8. Record your tests and observations in a table in the space below.

Q3(c)(i)

Short Answer 1 mark

From your observations in

Q3(c)(b)

Short Answer 1 mark

identify the cation and the anion present in each of FA 6, FA 7 and FA 8 by giving their formulae. cation anion FA 6 FA 7 FA 8

Q3(ii)

Short Answer 1 mark

Give an ionic equation for a precipitation reaction observed in (b)(i). Include state symbols. [Total: 16] Qualitative Analysis Notes 1 Reactions of aqueous cationsion reaction with NaOH(aq) NH

Q3(aq)

Short Answer 1 mark

aluminium,

Q3(aq)

Short Answer 1 mark

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

Q3(aq)

Short Answer 1 mark

no ppt. ammonia produced on heating barium,

Q3(aq)

Short Answer 1 mark

faint white ppt. is nearly always observed unless reagents are pure no ppt. calcium,

Q3(aq)

Short Answer 1 mark

white ppt. with high [Ca

Q3(aq)

Short Answer 1 mark

] no ppt. chromium( III),

Q3(aq)

Short Answer 1 mark

grey-green ppt. soluble in excess grey-green ppt. insoluble in excess copper( II),

Q3(aq)

Short Answer 1 mark

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

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),

Q3(aq)

Short Answer 1 mark

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

Q3(aq)

Short Answer 1 mark

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

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,

Q3(aq)

Short Answer 1 mark

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

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,

Q3(aq)

Short Answer 1 mark

gives cream ppt. with Ag

Q3(aq)

Short Answer 1 mark

(partially soluble in NH

Q3(aq)

Short Answer 1 mark

) iodide,

Q3(aq)

Short Answer 1 mark

gives yellow ppt. with Ag

Q3(aq)

Short Answer 1 mark

(insoluble in NH

Q3(aq)

Short Answer 1 mark

) nitrate,

Q3(aq)

Short Answer 1 mark

liberated on heating with OH

Q3(aq)

Short Answer 1 mark

and Al foil nitrite,

Q3(aq)

Short Answer 1 mark

liberated on heating with OH

Q3(aq)

Short Answer 1 mark

and Al foil sulfate,

Q3(aq)

Short Answer 1 mark

gives white ppt. with Ba

Q3(aq)

Short Answer 1 mark

(insoluble in excess dilute strong acids) VXO?WH

Q3(aq)

Short Answer 1 mark

gives white ppt. with Ba

Q3(aq)

Short Answer 1 mark

(soluble in excess dilute strong acids) 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 (ppt. dissolves with excess CO chlorine, Cl bleaches damp litmus paper hydrogen, H ?pops? with a lighted splint oxygen, O relights a glowing splint 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. 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 caesiu m 132. 9 barium137.3 franciu m radium boron 10.8 13 Al aluminium 27.0 31 Ga gallium 69.7 49 In indium 114.8 thallium204.4 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 hafnium 178. 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 technetiu m rhenium 186. 2 107 Bh bohrium iron 55.8 44 Ru ruthenium 101.1 76 Os osmium 190.2 108 Hs hassium Co cobal t58.9 45 Rh rhodium 102.9 iridium192.2 109 Mt meitnerium nicke l58.7 46 Pd palladium 106. 4 platinum 195.1 110 Ds darmstadtiu m copper 63.5 47 Ag silver 107. 9 79 Au gold 197. 0 111 Rg roentgenium zinc 65.4 48 Cd cadmiu m 112.4 80 Hg mercury 200. 6 112 Cn copernicium fleroviu m livermorium nitrogen 14.0 phosphorus 31.0 33 As arseni c 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 argon 39.9 36 Kr krypto n 83.8 54 Xe xenon 131. 3 86 Rn radon 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

Board	CAIE
Level	A Level
Subject	Chemistry
Code	`9701`
Year	2021
Session	Oct/Nov
Paper No.	Paper 33
Q&A	61 questions

Chemistry 2021 · Oct/Nov · Paper 33

Questions & Model Answers 61 Qs

Paper Details