Key Stage 3 Science Book 1 Assessments
Mixing, Dissolving and Separating (Blue level) Answers
1. Hamid is going to heat sodium chloride and water in a beaker. How can he carry out his experiment as safely as possible? [4 marks]
(the answer should contain four of the following)
1) Use a tripod and gauze to put the beaker on
2) Use a heat proof mat
3) Wear goggles
4) Leave the beaker to cool before touching it
5) Heat it gently with a Bunsen burner
6) Do not eat or drink while carrying out the procedure
7) Any other suitable response relating to safety
Difficulty level: moderate
Skill level: knowledge
2. Anne has set up an experiment to grow a crystal. It looks like this:
A week later the crystal is larger. Which of these is a correct explanation as to why? [1 mark]
d)
Difficulty level: easy
Skill level: application
3. Which of the following is not a mixture? [1 mark]
a)
Difficulty level: easy
Skill level: knowledge
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
4. Which of these techniques is not involved in obtaining salt from rock salt? [1 mark]
d)
Difficulty level: moderate
Skill level: knowledge
5. Which two processes are involved in distillation? [2 marks]
d), e)
Difficulty level: moderate
Skill level: knowledge
6. Match the description to the picture. [3 marks]
Two elements
An element
Mixture of an element and a compound
A compound
Mixture of two compounds
Difficulty level: moderate
Skill level: application
7. Why is water not the only solvent we use to remove stains? [2 marks]
(the answer should contain the following)
1) Some materials are insoluble in water
2) But they are soluble in other solvents
Difficulty level: easy
Skill level: knowledge
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
8. After a hit and run accident involving a car, the police collected some samples of paint from the crime scene. They have a suspect. How can the paint be tested to help the police confirm if they have the correct suspect or not? [2 marks]
(the answer should contain the following)
1) Use chromatography to separate the dyes
2) Use a sample from the crime scene and a sample from the suspect’s car to see if they match
Difficulty level: easy
Skill level: knowledge
9. What is produced when copper reacts with oxygen? [1 mark]
d)
Difficulty level: easy
Skill level: application
10. How would you separate water from a solution of copper sulfate? [2 marks]
(the answer should contain the following)
1) Heat the solution in a flask to evaporate the water
2) Distil the vapour/use a Liebig condenser to condense the water
Difficulty level: moderate
Skill level: application
11. Leroy used chromatography to investigate the food colourings used in some of his favourite sweets. Here’s a black and white diagram of the chromatogram, which shows his results.
Which two sweets probably contained the same mixture of food colourings? [1 mark]
d)
Difficulty level: moderate
Skill level: evaluation
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
12. Leroy used chromatography to investigate the food colourings used in some of his favourite sweets. Here’s a black and white diagram of the chromatogram, which shows his results.
What is the best conclusion that Leroy could make about sweets C and D? [1 mark]
d)
Difficulty level: moderate
Skill level: evaluation
13. Look carefully at this table of results.
How can the results table be improved? Select three possibilities. [3 marks]
a), c), e)
Difficulty level: difficult
Skill level: application
14. Emma is making jelly. In order to make it dissolve quickly, should Emma put the block of jelly in whole, or break it into cubes? Explain your answer. [2 marks]
(the answer should contain the following)
1) She should break it into cubes
2) There is greater surface area for the solvent (water) to reach
Difficulty level: easy
Skill level: application
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
15. Ben and Lucy investigated how much copper sulfate would dissolve in 100 cm3 of water at different temperatures. This is a graph of their results.
What do their results tell them? [2 marks]
(the answer should contain the following)
1) The hotter the water the more copper sulfate dissolves
Difficulty level: easy
Skill level: evaluation
16. Keisha has noticed that the tap water in the laboratory leaves a white substance around the tap when it dries up. Why has this happened? [2 marks]
(the answer should contain the following)
1) The water has evaporated
2) Leaving behind limescale/calcium salts/substances that were dissolved in it
Difficulty level: easy
Skill level: evaluation
© HarperCollinsPublishers 2014