Form/Class
Teachers’ Club Science – Structured questions
Teachers’ Club Science
Chemistry
Name
Structured Questions: Forensic science
The information below shows some physical properties of different powders.
Name
calcium carbonate
copper(I) oxide
sucrose
sodium chloride
Colour
white
red/brown
white
white
Is it soluble in water?
No
No
Yes
Yes
Melting point (°C)
825
1232
186
801
1
Name the two elements that make up copper(I) oxide
2
You have a mixture of calcium carbonate and sodium chloride. Describe the method you would use
to separate them.
3
A forensic scientist heated an unknown white powder until it melted. She recorded the temperature
at which it melted as 802°C.
a Which of the substances in the table is the powder most likely to be?
b Suggest why the melting point wasn't exactly the same as shown in the table.
© Smart Learning Ltd 2015
http://smart-learning.co.uk/teachers-club/teachers-club-science/
1
Teachers’ Club Science – Structured questions
Teachers’ Club Science
Chemistry
Form/Class
Name
Answers
1. Copper and oxygen
2. Add water to the mixture and stir. The sodium chloride will dissolve.
Filter the mixture. The substance left on the filter paper is calcium carbonate.
Leave the filtrate in an evaporating dish in a warm place. The water will evaporate leaving sodium
chloride in the dish.
3. a. Sodium chloride
b. It is contaminated with another substance, so it is not pure/it is a mixture.
2
http://smart-learning.co.uk/teachers-club/teachers-club-science/
© Smart Learning Ltd 2015