WA2 Practice Paper: Weighted Assessment 2 — mark scheme (print)

Back to WA2

Question paper PDF

QuizQuipPractice Series

QQ/S2SCI/WA2

Secondary 2 · Lower Secondary Science (G2 / G3)

Mark scheme

Weighted Assessment 2

WA2 Practice Paper · Maximum mark: 30

Notes for markers

Award one mark for each point marked [1], up to the marks shown for the part.
Accept answers worded differently that show the same understanding.
Units are required where the answer line shows one. ecf: allow an error carried forward.

Section A: Multiple-choice questions[10 marks]

Question	Answer
1	ARusting is a reaction of iron with oxygen in the presence of water.	1
2	CAn acid and an alkali react to form a salt and water.	1
3	BGreen plants and algae make food by photosynthesis, so they are producers.	1
4	DBurning magnesium forms a new substance, magnesium oxide, and the change is not easily reversed.	1
5	AEach arrow points from the organism being eaten to the organism that gains the energy.	1
6	CAcids turn blue litmus red.	1
7	BDecomposers feed on dead material and return nutrients to the soil.	1
8	DTemperature is a non-living factor. The others are living organisms or caused by them.	1
9	AA new colour and a gas that was not there before are signs of a chemical change.	1
10	CAn animal that hunts and eats another animal is a predator. The aphid is the prey.	1

Section B: Structured questions[20 marks]

Question	Answer and marking points	Marks
1(a)	Nail Q. It has both air (oxygen) and water, which rusting needs. Q [1] Both oxygen/air and water are present [1]	2
1(b)	Boiling removes dissolved air, and the oil stops fresh air dissolving. Without oxygen the iron does not rust. Little or no oxygen / air [1] Oil keeps air out, or boiled water has had air removed [1]	2
1(c)	The paint keeps water and oxygen away from the iron. Stops water and oxygen reaching the iron [1]	1
	Total for Question 1	5
2(a)	Bubbles of gas are given off, and the magnesium ribbon gets smaller. Bubbles / a gas is produced [1] Magnesium disappears or gets smaller, or the tube becomes warm [1] Accept any two correct observations.	2
2(b)	Hydrogen. It burns with a squeaky pop when a lighted splint is held at the mouth of the tube. Hydrogen [1] Lighted splint gives a squeaky pop [1]	2
2(c)	Blue [1]	1
	Total for Question 2	5
3(a)	Algae [1]	1
3(b)	The guppy is a predator of the mosquito larva, or the kingfisher is a predator of the guppy. A correct predator [1] Its matching prey [1]	2
3(c)	The number of mosquito larvae rises, because fewer of them are eaten by guppies. Number of larvae increases [1] Less predation / fewer are eaten [1]	2
	Total for Question 3	5
4(a)	Biotic: the number of grasshoppers (or any living organism). Abiotic: soil moisture, temperature or light intensity. One living factor [1] One non-living factor [1]	2
4(b)	Grasshoppers feed on the grass. Less grass means less food, so fewer grasshoppers survive. Less food for the grasshoppers [1] Fewer survive or the population falls [1]	2
4(c)	Decomposers (bacteria and fungi). Decomposers / bacteria / fungi [1]	1
	Total for Question 4	5

— End of mark scheme —