- Ibrahim and Emmanuel have been investigating the amount of copper sulfate that can be dissolved in water at different temperatures. They added copper sulfate until
no more would dissolve and they carefully measured the mass of the copper sulfate
they added. Here are their results.

+ Temperature of water / °C
20
30
40
50
60
70
80

+Mass of copper sulfate dissolved / g
22
24
28
32
30
46
58

a. What is the range of temperatures that the boys used?
b. What interval did they use for the temperatures?
c. Name a variable the boys should have kept the same.
d. Which is the independent variable?
e. What conclusion can the boys make from their results?