Chemistry Paper 3 Marking Scheme
KCSE CLUSTER TESTS 25
Chemistry Paper 3
-Complete table -CT 1 mk
-Decimal -D 1 mk
-Accuracy -A 1 mk
-Principal of average PA 1 mk
-Final Answer FA 1 mk
05 mks
Complete table mark.
A ward this mark if the following conditions are met:
i. Complete table with 3 titre values 1 mk
ii. Incomplete table with 2 titrations ½ mk
iii. Incomplete table with 1 titration 0 mk
Penalties
- Wrong arithmetic.
-Inverted table.
-Burete reading greater than 50 unless explained.
NB penalties ½ mk for each of these penalties to a maximum of ½ mk.
Accuracy mark
-If one titre value is within 1 mk
-If one titre value value is within 0.2 of sch value ½ mk
-If no titre value is within 0.2 of sch value 0 mk
Principals of averaging
i. If 3 consistent values are averaged 1 mk
ii. If 3 titrations are done and only 2 are consistent and averaged 1 mk
iii. If 2 titrations are done and are consistent and are averaged. 1 mk
iv. If 3 or 2 titrations are done and are inconsistent and are averaged. 0 mk
v. If 3 titrations are done are consistent and only 2 are averaged 0 mk
vi. If one titration is done
0 mk
Penalties
i. Penalise½ mk for wrong arithmetic.
ii. Penalise ½ mk if no working is in shown but answer given is correct.
iii. Penalise½ mk if answer given is in less than 2 d.p
Iv If wrong units are used penalize ½ mk
14 marks
14 marks
12 marks