Bishops Grade 8
Term 2 Common Test
Formula of compounds, Mixtures & separation
and Scientific Measurement
K Warne
40 Marks 40 Minutes
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Formula: area of a rectangle = length x width
A Periodic Table is given on the last page.
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Question 1 Multiple Choice
Write only the question number and the letter corresponding to the correct or best answer.
1.1
The correct formula of the substance calcium oxide is…
(2)
A CaO2
B Ca2O
C CaO
D 2CaO
1.2
Which of the following represents a mixture?
A milk
B carbon dioxide
C pure table salt
D distilled water
(2)
1.3
Two miscible liquids are best separated by…
A
filtration.
B
using a separating funnel.
C
fractional distillation.
D
distillation.
(2)
1.4
Which instrument is used to measure the volume of an irregular shaped object?
A
A pipette
B
A burette
C
A liebeg condenser
D
A Eureka can
(2)
1.5
When rounded off, a length of 5,6 cm is equal to…
A 0,56 m
B 0,056 m
C 5,6 m
(2)
D 0,0056 m
5 x (2) = [10]
Question 2: Formulae and Compounds
2.1
Write chemical formula for the following compounds;
2.1.1 sodium iodide
2.1.2 aluminium sulphide
2.2
Write the chemical name for the compound Pb3N2.
Question 3: Mixtures
Mixtures are very different to compounds. State clearly how compounds are different to mixtures by
describing briefly but clearly the;
3.1
composition of compounds
3.2
separation of compounds into their elements.
(1)
(2)
(2)
[5]
(1)
(1)
[2]
Question 4: Separation techniques
4.1
Your class is given a practical task. You are given the following four mixtures which you are asked to
separate;
a) salt and sand, b) sea water, c) oil in water
d) ink.
The apparatus below can be used to separate a solvent from its solution.
4.1.1
4.1.2
4.1.3
Which of the four mixtures listed above can be separated in the distillation flask?
Using your answer from question 4.1.1, name the substance that would collect at A?
What is the name of the piece of apparatus labelled B in the diagram above?
(1)
(1)
(1)
4.2
One of the mixtures listed above could be separated using a filter funnel.
4.2.1 Identify this mixture.
(1)
4.2.2 Explain briefly what you would need to do to the mixture before you could make use of the
filter funnel?
(1)
4.2.3 Name the substance(s) in this mixture that would be the residue once the filtration
process was complete?
(1)
4.2.4 Name one other piece of apparatus you would need to use with a Bunsen burner and tripod
stand and gauze to obtain the second substance from the filtrate.
(1)
4.3
There are still two mixtures that your class must separate. You have the following methods left to
use; centrifuging, a separating funnel and chromatography.
4.3.1 Which of the mixtures given at the start of question 4 would you place in the separating
funnel?
(1)
4.3.2 Name the substance that you would expect to run out of the separating funnel first.
(1)
4.4
Some mixtures are known as suspensions. Fully describe a suspension.
(2)
[11]
Question 5 Scientific Measurement
5.1
Physical quantities are measured according to an international system. The base units for this system
are given in the table below: Write down the missing information alongside the question numbers
on your answer paper.
Other units
QUANTITY
SI UNIT
Word and (symbol)
5.1.1
mass
3.1.3
metre (m)
5.1.2
5.1.4
inch, yard
pound, ton
hour, year
(4)
5.2
5.3
Assume that the shape shown below is a cube.
5.2.1 Accurately measure the length of side A in
millimetres using a ruler. Write this length on
your answer paper.
(1)
5.2.2 Convert this length to metres.
(1)
5.2.3 Calculate the area (in m2) of one side of this cube. (3)
A
When taking measurements it is important to avoid an error which is illustrated in the picture below.
5.3.1
5.3.2
5.3.3
Which of the positions A, B or C is the correct one from which to take the reading?
(1)
What is this error called?
(1)
Read and record the volume of liquid in the measuring cylinder accurate to one decimal
place.
(1)
[12]
TOTAL 40
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