6031q4specimen

Extracted Content: 6031q4specimen

Page 1

Extracted Text

Candidate Name Centre Number Candidate Number

Ta

ZIMBABWE SCHOOL EXAMINATIONS COUNCIL

General Certificate of Education Advanced Level

CHEMISTRY 6031/4

PAPER 4 Practical Test

SPECIMEN PAPER 2 hour 30 minutes

Candidates answer on the question paper.
Additional materials:
As listed in Instructions to Supervisors
Electronic calculator

TIME 2 hour 30 minutes
INSTRUCTIONS TO CANDIDATES

Write your name, Centre number and candidate number in the spaces at the top of this page.
Answer all questions.
Write your answers in the spaces provided on the question paper.

INFORMATION FOR CANDIDATES
The number of marks is given in brackets [ ] at the end of each question or part question.

Y ou are advised to show all working in calculations.
Use of a Data Booklet is unnecessary.

FOR EXAMINER’S USE

Qualitative analysis notes are printed on pages 10 and 11. 1

2

3

TOTAL

This question paper consists of 11 printed pages and 1 blank page.

Copyright: Zimbabwe School Examinations Council, Specimen paper.

©ZIMSEC [Turn over

---

Page 2

Extracted Text

Y ou are required to estimate the percentage composition of iron (II) ions in a brown contraceptive pill. The major component of the pill is, ferrous fumarate, CaH2FeOs.

FA1

FA2

(a)

(b)

are three reddish brown contraceptive pills.

is a 0.001 moldm? KMnOs ap.

Weigh an empty small beaker.
Place FA 1 (the three pills) in the small beaker and weigh again.
Record your weighings in Table 1.1.

Table 1.1

mass of small beaker + FA1/g

mass of empty small beaker / g

mass of FA1 used /g [2]

Crush the three pills using mortar and pestle.

Transfer all the powder into the small beaker.

Using a measuring cylinder add 15 cm? of hot 1.0 moldm™“sulphuric
acid to the crushed pills in the small beaker and stir vigorously with a

glass rod.

Transfer all the contents of the beaker into a 250 cm? volumetric flask.
Make up to the mark with distilled water.

Mix the contents thoroughly by shaking and label this solution FA3.
Filter FA3 into a clean beaker

Pipette 25.00 cm? of the filtered FA3 into a conical flask and add
10.00 cm of 1.0 moldm sulphuric acid.

Titrate the contents of the conical flask with FA2.
Repeat the titration as many times as you think necessary to obtain

accurate results.

6031/4 Specimen paper

For

Use

---

Page 3

Extracted Text

(b) Record your burette readings in Table 1.2.

Table 1.2:

final burette reading /cm?

initial burette reading/ cm?

volume of FA2 used /cm* [15]

Summary

25.00 cm? of FA3 reacted with cm? of FA2.

Show which results you used to obtain this volume of FA2 by placing a tick
under the readings in Table 1.2.

In acidic conditions, MnO and Fe** ions react according to the following
half equations:

Mn0O,,,,+8H<em> +5¢ ===Mn?</em>

4{aq) (aq) (aq)

+4H,0,)

3+ - — ss GA2+
Fe; te Fen)

(c) Write a balanced equation for the reaction between Fe** and Mn0Oj,.

[1]
(d) — Calculate the number of moles of MnO ‘(eq) in the volume of FA2

which reacted with 25 cm? of FA3.

[1]

6031/4 Specimen paper

[Turn over

For

Use

---

Page 4

Extracted Text

4

(e) Calculate the number of moles of Fe; in 25.00 cm@of FA3.

(3) Determine the mass of Fe?*in the brown contraceptive pill.

@\,, (Fe) : 55.86

[2]

(g) Estimate the percentage composition of iron in the brown contraceptive
pill.

(h) Given that the structural formulae of ferrous fumarate is

O wo OH O
\ | | 4 .
C—C=c—c + Fe’

, \

Suggest why the value of the percentage composition of iron
determined in the experiment is much higher than the actual value.

6031/4 Specimen paper

For

Use

---

Page 5

Extracted Text

5

F
@ Describe and explain how the end point is observed in this analysis. Examiner's

Use

woe [2]
[Total:20]

6031/4 Specimen paper

[Turn over

---

Page 6

Extracted Text

ASSESSMENT OF PLANNING SKILLS DO NOT CARRY OUT YOUR PLAN.

Sodium is a very reactive metal which is stored under oil to prevent contact
with air and water vapour.

The reaction of sodium with water can be represented by the equation,

2Na,)+2H,0,) >2NaOH +H).

You are required to determine the A; of sodium using a given sample of
sodium metal basing on the above reaction.

Present your plan as a sequence of numbered steps and draw a diagram
showing the set up of the experiment. Y our plan should show how you
would use your results to determine the A; of sodium.

Assume you are provided with the following:

a piece of sodium metal
water

thistle funnel

absorbent paper

rubber stopper

delivery tube
measuring cylinder
beaker

[molar gas volume, Vm, = 24 dm? mol"! at r.t.p.]

The plan

6031/4 Specimen paper

For

Use

---

Page 7

Extracted Text

[Total :10]

6031/4 Specimen paper
[Turn over

---

Page 8

Extracted Text

3

(a)

(b)

(9)

FAL is a solution containing one cation and two anions.

You are required to identify the ions in FA1 by carrying out the tests described
in the table.

In all the tests, the reagents should be added gradually until no further change is
observed, with shaking after each addition. Take a portion of FA1 to be about
2 cm’.

Record your observations and deductions in the spaces provided.

Your answers should include,

(a) details of colour changes and precipitates formed,

(ii) the names of gases evolved and details of the test used to identify each one.

You should indicate clearly at what stage in a test a change occurs writing any
deductions you may make alongside the observation on which they are based.

test observations [13] deductions [8]

Describe the appearance of
FAI.

To a portion of FA1, add
NaOHaazg) until in excess
and then heat

To a portion of FAI, add
NHa(aq) until in excess.

6031/4 Specimen paper

For

Use

---

Page 9

Extracted Text

(d)

(e)

®

(g)

To a portion of FAI, add
BaClhag)

followed by dilute
HC/

To a portion of FA1, add
Pb (NO3)aq).

To a portion of FA1, add
dilute HCI.

To a portion of FA1, add
dilute HNO3

followed by AgNO3@aq).
Summary:
cation (]
anions and [2]
[Total: 20]
6031/4 Specimen paper

[Turn over

---

Page 10

Extracted Text

10 QUALITATIVE ANALYSIS NOTES

[Key ppt = precipitate]

1 Reactions of aqueous cations

reaction with

NaOH (aq) NH,(aq)
aluminium, white ppt. white ppt.
AL*(aq) soluble in excess insoluble in excess
ammonium, ammonia produced on heating
NH,*(aq)
barium, no ppt. (if reagents are pure) no ppt.
Ba?*(aq)
calcium, white ppt. with high [Ca2* (aq)] no ppt.
Ca?*(aq)
chromium(III), grey-green ppt. soluble in excess grey-green ppt.
Cr3*(aq) giving dark green solution insoluble in excess
copper(II), pale blue ppt. blue ppt. soluble in excess
Cu2+(aq) insoluble in excess giving dark blue solution

iron(II),
Fe2+(aq)

green ppt.
insoluble in excess

green ppt.
insoluble in excess

iron(II),
Fes+(aq)

red-brown ppt.
insoluble in excess

red-brown ppt.
insoluble in excess

lead(II),
Pb?*(aq)

white ppt.
soluble in excess

white ppt.
insoluble in excess

magnesium,
Mg?*(aq)

white ppt.

insoluble in excess

white ppt.
insoluble in excess

manganese(II), off-white ppt. off-white ppt.
Mn?*(aq) insoluble in excess insoluble in excess
zinc, white ppt. white ppt.

Zn2*(aq) soluble in excess soluble in excess

[Lead(II) ions can be distinguished from aluminium ions by the insolubility of lead(II) chloride.]

6031/4 Specimen paper

---

Page 11

Extracted Text

11

000 Doon oon coomo00

i MGGHE
OOMo000 00 ,M00n0noomooo
OO 2
O00 0000 o OOOO 00 OMMoO0 00000 mm "moo
oO 24000 OBA O00 Bsa oan 0000

OBa0L Momo DM "O00
OMe OBE O
0 000 OBA
000 10 OBS0 OOO MOM OO aA ,o00
emmo0 OBA
OM0e 0b OMOM0 00 @ ,00000

O00 OBO
Invtinaytitey 2 (Mo owowomoomon oo o Sonos
wf
eg ,f 000 DBE00 003i M0200 Oooo OED Monmoomo00
OM000mon0000

“00 DOM H CEO

O0 0 COW ot) p CMOM00 30000 0O0seseo0m0

DOM COMM OG 0 5) OBR0000 OOS See OO O00 oO EROOGS000 0OGAO0000 oO Oo
OOMIOO Ge 4 OMOO000W00 Sal 0003380

OOOMO00@ , 333A 1 DM O00 Sa00

OED00@ , 000 0 MOO smo

DOBSIOO GOO ,| MO00 3AM 0000 COOO00 0 oOo eo oomoooomoomoo

6031/4 Specimen paper

---

Page 12

Extracted Text

12 BLANK PAGE

6031/4 Specimen paper

---