Use this ZIMSEC O-Level Combined Science Paper 2 2023 marking scheme for checking answers, revision, and exam preparation in Zimbabwe.
A free account is needed to download. Sign in or create one
Questions: Cambridge International O-Level Combined Science Paper 2 2023 Question Paper
This is the ZIMSEC O-Level Combined Science marking scheme for Paper 2 from 2023. It shows how marks are awarded, so you can mark your own answers to the matching question paper. See the question paper.
COMBINED SCIENCE 2023 PAPER 2 MARKING GUIDE
1 (a) (i) transport (manufactured) food: AW
(ii) provide cells for growth (of stem and roots)/ AW
[1]
(b)
(c) (i) plasma
[1]
(ii) transport medium; distribution of water; hormones; nutrients/AW max [1]
(d) homeostasis; defense/AW
[1]
2. (a) (i) carbon dioxide
[1]
(ii) bubble through limewater; turns limewater milky
OR use bicarbonate indicator; turns yellow
max [2]
(b) (i) alveolus/ air sacs
[1]
(ii) gaseous exchange/ / AW
[1]
(iii) large surface area; thin layer of moisture; large network of blood capillaries; thin walls max [2]
3 (a) (i) 12
[1]
(ii) 2.8 .2
[1]
(iii) ionic
[1]
(iv) high melting point/solid at room temperature; crystalline; high boiling point; hard and brittle ;conduct electricity when molten or in dissolved in water max [1]
(b) moles $=$ mass $/ \mathrm{Mr} \quad / 47 / 94=; 2$ (moles)
Concentration $=$ moles $/$ volume $/ 2 / 0.5=: 4 \mathrm{~mol} / \mathrm{dm}^{3}$ (correct unit)
max [3]
4 (a) (i) 1. electrolyte
[1]
2. electrode/cathode
[1]