Mark Scheme (Results) January 2020 - IG Exams



Mark Scheme (Results)

January 2020

Pearson Edexcel International GCSE in

Chemistry (4CH1)

Paper 1C



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January 2020

Publications Code 4CH1_1C_msc_2020305

All the material in this publication is copyright

? Pearson Education Ltd 2020



General Marking Guidance

?

All candidates must receive the same treatment. Examiners must

mark the first candidate in exactly the same way as they mark the

last.

?

Mark schemes should be applied positively. Candidates must be

rewarded for what they have shown they can do rather than

penalised for omissions.

?

Examiners should mark according to the mark scheme not

according to their perception of where the grade boundaries may

lie.

?

There is no ceiling on achievement. All marks on the mark scheme

should be used appropriately.

?

All the marks on the mark scheme are designed to be awarded.

Examiners should always award full marks if deserved, i.e. if the

answer matches the mark scheme. Examiners should also be

prepared to award zero marks if the candidate¡¯s response is not

worthy of credit according to the mark scheme.

?

Where some judgement is required, mark schemes will provide the

principles by which marks will be awarded and exemplification may

be limited.

?

When examiners are in doubt regarding the application of the mark

scheme to a candidate¡¯s response, the team leader must be

consulted.

?

Crossed out work should be marked UNLESS the candidate has

replaced it with an alternative response.



Question

number

1 (a) (i)

Notes

Marks

argon / helium

ACCEPT Ar / He

1

(ii)

nitrogen

ACCEPT N2

1

(iii)

carbon dioxide

ACCEPT CO2

1

ACCEPT CO2

1

(iv)

(b)

Answer

carbon dioxide

(i)

S + O2 ? SO2

(ii)

acid rain

1

ACCEPT an adverse

effect of acid rain

e.g. kills fish, damages

plants, corrodes

limestone/marble

buildings/statues etc.

1

IGNORE toxic/pollutant

Total 6



Question

number

2 (a)

Answer

name of the part of the atom

labelled Z

(b)

Notes

nucleus

number of protons in this

atom

12

number of the group that

contains this element

2

number of the period that

contains this element

3

charge on the ion formed from

this atom

2+

?

?

?

Marks

5

ACCEPT +2 / Mg2+

calculate sum of mass numbers multiplied by

percentage abundances

divide answer by 100

give answer to one decimal place

Example calculation

M1 (24 x 79.2) + (25 x 10.0) + (26 x 10.8) OR 2431.6

M2 2431.6 ¡Â 100 OR 24.316

REJECT if correct

working given but

incorrectly evaluated

ALLOW ECF from M1

(24 x 0.792) + (25 x

0.100) + (26 x 0.108)

OR 24.316 with or

without working

scores M1 and M2

M3 24.3

3

ALLOW ECF from M2 if

calculated answer is

to 1dp

Total 8

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