Chemistry Reference
In-Depth Information
a
Indicate on the diagram, using an arrow,
where heat is applied.
6
The following instructions were used to prepare
magnesium sulfate crystals, MgSO
4
.7H
2
O.
Step 1
Measure 50 cm
3
of dilute sulfuric acid into
a beaker and warm the solution.
Step 2
Using a spatula, add some magnesium
oxide and stir the mixture. Continue adding the
magnesium oxide until excess is present.
Step 3
Separate the excess magnesium oxide from
the solution of magnesium sulfate.
Step 4
Heat the solution until crystals form.
Obtain the crystals and dry them.
a
Why is the sulfuric acid warmed? [1]
b
How would you know when excess magnesium
oxide is present in
Step 2
? [1]
c
What method is used in
Step 3
? [1]
d
Why must care be taken when drying the crystals
in
Step 4
?
[1]
b
The crystals change colour from ______ to
______ . [1]
c
What is the purpose of the ice? [1]
d
Why is the tube open at point
W
? [1]
[Total: 4]
(Cambridge IGCSE Chemistry 0620 Paper 61
Q6 June 2010)
4
Malachite is a naturally occurring form of copper
carbonate. Outline how a sample of copper metal
could be obtained from large lumps of malachite in
the laboratory.
Copper is one of the least reactive metals. Your
answer should include any chemicals used and
conditions. [6]
[Total: 6]
(Cambridge IGCSE Chemistry 0620 Paper 61
Q7 June 2010)
[1]
e
Explain how the method would differ if
magnesium carbonate was used instead of
magnesium oxide. [2]
[Total: 6]
(Cambridge IGCSE Chemistry 0620 Paper 61
Q2 November 2010)
5
Ethene can be prepared by passing ethanol vapour
over hot aluminium oxide.
7
A concentrated solution of sodium chloride was
electrolysed using the apparatus below.
ethene
mineral wool
+
-
positive
electrode
negative
electrode
water
concentrated
aqueous sodium chloride
and Universal Indicator
a
Complete the boxes to show the
chemicals used.
[1]
b
Show on the diagram with two arrows
where the heat is applied.
[2]
One observation noted was that the Universal
Indicator turned purple at the negative electrode.
a
What observation would be made at
both
electrodes? [1]
b
Why did the indicator turn purple at the negative
electrode?
c
Why must the delivery tube be removed from
the water before the heating is stopped? [2]
[Total: 5]
(Cambridge IGCSE Chemistry 0620 Paper 61
Q1 November 2010)
[1]
c (i)
Name the product formed at the positive
electrode.
[1]
(ii)
Suggest the effect of this product on the
Universal Indicator. [1]
[Total: 4]
(Cambridge IGCSE Chemistry 0620 Paper 61
Q6 November 2010)
