Year 8 Science (2015)
Name: ____________________
Revision: Making new substances.
Directions to students:
You are not permitted to use the following during the test: notes, textbooks, blank sheets of
paper and/or white out liquid/tape.
Read the questions carefully and follow all instructions.
Part A – Multiple choice questions
Choose the response that is correct or best answers the question, and write your answer in the table
below.
Question
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2
3
4
5
6
7
Answer
1
Which of the following is an example of a physical change?
a) An egg cooking.
b) A piece of iron rusting.
c)
Ice melting.
d) Burning a piece of magnesium.
2
Which of the following is an example of a chemical change?
a) Two chemicals are mixed and heat is produced.
b) Two chemicals are mixed and a permanent colour change occurs.
c) Two chemicals a re mixed and bubbles of a gas are observed.
d) All of the above
3
In the following chemical reaction
Iron + sulphur  iron sulphide
a) Iron is a reactant.
b) Iron sulphide is a reactant.
c)
Sulphur is a product.
d) Iron, sulphur and iron sulphide are reactants.
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4
In the chemical sodium hydroxide (NaOH) there is
a) 1 type of atom.
b) 2 different types of atoms.
c)
3 different types of atoms.
d) 4 different types of atoms.
5
In one molecule of water (H2O) there are
a) 2 hydrogen atoms
b) 2 oxygen atoms
c)
2 hydrogen atoms and 2 oxygen atoms.
d) Not enough information to work out it’s formula
6
What is a ‘product’ of a chemical reaction?
a) A mathematical operation.
b) A substance you start with before a chemical reaction takes place
c) A substance created by a chemical reaction.
d) A non-reversible reaction.
7
What is the name of the element that has the symbol Pb (see Periodic Table)
a) Potassium
b) Phosphorus
c)
Polonium
d) Lead.
8
What is the symbol for the element strontium (see periodic table)
a) S
b) St
c)
Str
d) Sr
9
When cleaning up after an experiment you should:
a) Put hot equipment away ONLY when it is cooled down enough to hold safely.
b) Ask your teacher or see if there is a special waste container for chemicals.
c)
Wipe down the benches.
d) All of the above.
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10 When heat is applied to a solid the following changes in state usually occur:
a) gas  liquid  solid
b) solid  liquid  gas
c) solid  gas  liquid
d) liquid  solid  gas
Part B – Short answer questions
Answer all questions.
1
List five indictors of a chemical reaction:
2 Water can be in any of three states – solid, liquid or gas. How can you tell that changes between
these states are only physical changes?
3
Indicate whether the following observations below involve either a physical or chemical change.
Observation
Physical or chemical change
Steam condensing on a mirror
An ice cube melting
Two chemicals are mixed and the temperature
decreases
Cooking meat for dinner
Burning gas in a Bunsen burner
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4
Solid calcium carbonate can be decomposed by heat to form solid calcium oxide and carbon
dioxide gas. The reaction that takes place is
calcium carbonate  calcium oxide + carbon dioxide
a) list the products in the above reaction
b) Explain whether this reaction is a physical or a chemical change.
c) In one experiment 10 grams of calcium carbonate produced 8 grams of calcium oxide. What
mass of carbon dioxide gas was produced?
5
Write word equations for the following. For example:
When sodium metal reacts with chlorine gas, they form sodium chloride.
Sodium + Chlorine  Sodium Chloride
a) Solid carbon dioxide turns directly into carbon dioxide gas when heated.
b) Carbon dioxide and water vapour (both gases) are formed when butane gas burns in the
presence of oxygen gas.
c) Human cells get their energy by glucose reacting with oxygen to form carbon dioxide and
water
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6 Use the periodic table attached to complete the following table. The first two columns have
been done for you.
Name
Chromium
Water
Symbol /
Formula
Cr
H2O
Element /
compound
Element
Compound
Silver
Carbon
dioxide
Cl
Sodium
chloride
N
NaCl
Part C – EXTRA EXTRA EXTRA hard questions
Balance the following chemical equations
a) ___H2 + O2  2H2O
b) CH4 + ___ O2  CO2 + 2H2O
c) 2NaCl + F2  ___NaF + Cl2
End of paper.
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