Year 8 Science TEST – Chemical Change
[Total = 25 marks]
Name: Answers/solutions____________
Please circle the most correct answer
1.
A.
B.
C.
D.
Which of the following is NOT an example of a chemical property?
flammability
malleability
toxicity
reactivity
1 mark
2.
A.
B.
C.
D.
The physical property of rubber bands that makes them most useful are
reactivity
ductility
malleability
elasticity
1 mark
3.
A.
B.
C.
D.
4.
A.
B.
C.
D.
Reactivity is a measure of
how easily a substance combines with other substances to produce new substances
how easily a substance catches fire
danger to your health caused by poisonous substances
how easily a substance can be drawn into wires
1 mark
Which of the following is NOT an example of a physical change?
melting
freezing
combustion
evaporation
1 mark
5.
A.
B.
C.
D.
What statement is most true about when a chemical change takes place?
a new substance is formed that is easily reversed
a new substance is formed that is difficult to reverse
the state of the substance changes which is difficult to reverse
the state of the substance changes which is easily to reverse
1 mark
1
6.
A.
B.
C.
D.
Which of these would NOT be evidence of a chemical reaction taking place?
a precipitate forming
water freezing
bubbles appearing
a change in colour
1 mark
7.
A.
B.
C.
D.
8.
A.
B.
C.
D.
9.
A.
B.
C.
D.
10.
A.
B.
C.
D.
The chemical reaction between magnesium metal and hydrochloric acid is likely to result
in:
a bright white flame
a precipitate forming
a decrease in temperature
bubbling
1 mark
Sodium sulphate and barium chloride solutions react to form solid barium sulphate and
sodium chloride, which remains dissolved in the solution. The correct word equation
representing this chemical reaction is:
sodium sulphate + barium chloride → barium sulphate + sodium chloride
sodium sulphate + barium chloride = barium sulphate + sodium chloride
barium sulphate + sodium chloride → sodium sulphate + barium chloride
barium sulphate + sodium chloride = sodium sulphate + barium chloride
1 mark
For the chemical reaction in Question 8 what evidence would be observed to confirm it
had taken place?
a bright white flame
a precipitate forming
a decrease in temperature
bubbling
1 mark
The rate of a reaction is a measure of
how quickly a chemical reaction occurs
how quickly a physical change occurs
the cost of a chemical reaction
how quickly the reactants are made
1 mark
2
11.
A.
B.
C.
D.
Which are all ways to increase the rate of a chemical reaction?
increasing temperature, decreasing surface area, decrease reactants
increasing temperature, increasing surface area, increasing reactants
decreasing temperature, increasing surface area, decreasing reactants
decreasing temperature, decreasing surface area, increasing reactants
1 mark
12.
A.
B.
C.
D.
A catalyst will
slow down a chemical reaction and be gone at the end
slow down a chemical reaction and be present at the end
speed up a chemical reaction and be present at the end
speed up a chemical reaction and be gone at the end
1 mark
13.
A.
B.
C.
D.
14.
Heating causes an increase in the rate of a chemical reaction. An explanation to explain
this is:
the particles move faster and collide less
the particles move slower and collide less
the particles move slower and collide more
the particles move faster and collide more
1 mark
The word equation describing a chemical reaction is: methane + oxygen → carbon
dioxide + water
The reactants for this reaction are:
A.
B.
C.
D.
methane
methane and oxygen
methane, oxygen and carbon dioxide
methane, oxygen, carbon dioxide and water
1 mark
15.
A.
B.
C.
D.
The reaction in Q14 is an example of what type of reaction?
precipitation
rusting
combustion
corrosion
1 mark
Short Answer:
16. List two differences between a Physical and a Chemical change
Physical – same elements/compounds present – easily reversible
Chemical – new elements/compounds – difficult to reverse
1 mark
3
17. In the following reactions, state which are the reactants and the products.
a. Magnesium + oxygen -----> Magnesium oxide
Reactants
Product
b. Magnesium + Hydrochloric acid -----> Magnesium chloride + Hydrogen
Reactants
Products
2 marks
18. Copper nitrate and hydrogen gas are produced when copper and nitric acid react. Write a
word equation for this reaction:
Copper + Nitric Acid  Copper Nitrate + Hydrogen
2 marks
19. What is corrosion? Give two examples of materials that corrode.
A chemical reaction that wears away a metal such as rusting of a metal.
Iron, Aluminium plus lots more
2 marks
20. Explain what rust is?
Iron + Oxygen  Iron Oxide which is rust. This is a form of corrosion
1 mark
21. Name two ways rusting can be minimised.
Paint the iron to stop oxygen reaching the iron.
Add a block of zinc (or coat with zinc) as this is more reactive and will protect the iron.
2 marks
4