Experimental chemistry - Chemistry - page 269

c Why does the mass of the beaker and contents
decrease?

a (i) Clearly label the electrodes on the
diagram.

[1] [1]

d Suggest the purpose of the cotton wool. [1] (ii) Suggest a suitable material to make the

electrodes. [1]
b Give two observations expected when the lead
bromide is heated to melting point.

e After how long did the reaction finish? [1]

f A second experiment was carried out using
hydrochloric acid at a lower temperature.
On the grid sketch a curve to show the
expected results for this experiment.
Label this curve C . [2]
[Total: 12]
(Cambridge IGCSE Chemistry 0620 Paper 06
Q6 November 2009)

[2]

c State two different safety precautions when
carrying out this experiment. [2]
[Total: 6]
(Cambridge IGCSE Chemistry 0620 Paper 06
Q2 June 2008)

17 Sulfur dioxide gas is denser than air and soluble in
water. A sample of sulfur dioxide can be prepared
by adding dilute hydrochloric acid to sodium
sulfite and warming the mixture. Study the
diagram of the apparatus used.

15 Leaves from trees contain a mixture of coloured
pigments which are not soluble in water. A
student was given these two instructions to
investigate the pigments in the leaves.
1 Crush some leaves to extract the coloured
pigments.
2 Use the liquid extract to find the number of
coloured pigments in the leaves.
a What would the student need in order to
effectively carry out instruction 1? [3]
b Describe an experiment to carry out instruction 2.
A space has been left below if you want to draw a
diagram to help answer the question. [4]
[Total: 7]
(Cambridge IGCSE Chemistry 0620 Paper 06
Q7 November 2009)

water

16 The diagram shows an experiment to pass
electricity through lead bromide. Electricity has
no effect on solid lead bromide. a Fill in the boxes to show the chemicals used.[2]

b Show by using an arrow, on the diagram, where
heat is applied.

d.c. power supply

[1]

c Identify and explain two mistakes in the
diagram. [2]
[Total: 5]
(Cambridge IGCSE Chemistry 0620 Paper 06
Q3 June 2008)

bulb

18 A student investigated the reaction between
potassium manganate( vii ) and a metallic salt
solution.
Two experiments were carried out.

LEAD
BROMIDE
TOXIC

Experiment 1
a About 1 cm 3 of aqueous sodium hydroxide was
added to a little of the salt solution A and the
observation noted.
observation green precipitate formed

heat