International GCSE
Chemistry Assessment
Elements, Compounds and Mixtures
Candidate Name :
Total Mark:
Answer All questions
1. (a) The box gives some methods used in the separation of mixtures.
Chromatography
Filtration
crystallization
fractional distillation
evaporation
simple distillation
Use words from the box to answer these questions.
(i) Identify the methods used to obtain pure water from sea water. (1 mark)
……………………………………………………………………………………………………………………………………………….
(ii) Identify the method used to separate the dyes in food coloring. (1 mark)
……………………………………………………………………………………………………………………………………………….
(iii) Identify the method used to obtain ethanol from a mixture of ethanol and water.
(1 mark)
……………………………………………………………………………………………………………………………………………….
(b) Complete the sentences by writing a suitable word in each blank space. (3 marks)
When salt is added to water and stirred until no more will ………………………………………,
A saturated solution forms.
The salt is the ……………………………………. .
The water is the ……………………………………… .
(Total = 6 marks)
2.
Some sugar is added to cold water in a beaker.
After some time, all the sugar dissolves and spreads throughout the water.
(a)
(i) Name the process that occurs which causes the sugar to spreads throughout the
water. (1 mark)
……………………………………………………………………………………………………………………………………………….
(ii) State two ways to make the sugar dissolve more quickly. (2 marks)
1)…………………………………………………………………………………………………………………………………………
2)…………………………………………………………………………………………………………………………………………
(b) Pure water can be obtained from the sugar solution using this apparatus.
X
Sugar
solution
(i) Name the process used to obtain pure water from the sugar solution. (1 marl)
……………………………………………………………………………………………………………………………………………….
(ii) Explain the purpose of the piece of apparatus labelled X. (1 mark)
……………………………………………………………………………………………………………………………………………….
(Total = 5 marks)
3. A teacher uses this apparatus to separate a mixture of ethanol and water.
B
A
(a) (i) Name this method of separation. (1 mark)
……………………………………………………………………………………………………………………………………………….
(ii) Name the change of state taking place at A. ( 1 mark)
……………………………………………………………………………………………………………………………………………….
(iii) Name the change of state taking place at B. (1 mark)
……………………………………………………………………………………………………………………………………………….
(Total = 3 marks)
4. A student does a chromatography experiment using ink 1, ink 2 and three known dyes A,
B and C. The student uses water as the solvent.
This is what she uses.
 A beaker
 A piece of chromatography paper with a pencil line drawn near the bottom of the
paper
 A solvent (water)
 ink 1, ink 2 and three known dyes A, B and C
(a) Describe how the student should set up and carry out her experiment. ( 3 marks)
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
The diagram shows the student’s chromatogram.
Solvent front
Pencil line
Ink
1
Ink
2
dye
A
dye
B
dye
C
(b) Deduce what conclusions can be made about the composition of ink 1. ( 1 mark)
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
(c) Suggest how the student could change the experiment to find the composition of ink 2.
(1 mark)
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
(d) Calculate the Rf value of dye C, giving your answer to 2 significant figures. (1 mark)
(Total = 6 marks)
5. The diagram shows the particles in four substances, A, B, C and D.
A
B
C
D
(i) Which substance contain single atoms of one element? ( 1 mark)
…………………………………………
(ii) Which substance is a compound? (1 mark)
…………………………………………
(iii) which substance would have the formula H2? (1 mark)
…………………………………………
(iv) Which substance is a mixture? Give the reason why the substance is a mixture. (2 marks)
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
(Total = 5 marks)