SDIS
Science
Grade 7
Revision WS – Elements and Compounds
1.
Look at the boxes.
Which
box contains:
(a) iron
only?
_____________
(b)
mixture of iron and sulfur? _____________
(c) iron sulfide only? _____________
2.
In the following list only three are compounds, underline them.
Mercury; pure water; carbon dioxide; sulfur; iron; iron sulphide
3.
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SDIS
6.
Science
Grade 7
Complete the following table:
Element name
Element symbol
Hydrogen
C
He
Lithium
Sodium
Ne
Oxygen
F
Potassium
Calcium
Magnesium
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SDIS
Science
Grade 7
7. The figure below represents the Periodic Table of elements and the line that separates the
elements in two different categories according to their properties. Write in the boxes the name of
those two categories.
8. A new drink has two edible dyes in it. How would you show that there are two different dyes in
the drink? What technique would you use? Draw a diagram and describe the process.
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SDIS
Science
Grade 7
9. Match the term to its correct definition.
10. The graph shows how the solubilities of 8 substances change with temperature.
a) What is the solubility of potassium bromide (KBr) at 80oC? ________________
b) Which compound shows the least variation of solubility with temperature? ____________
c) Which compound shows a decrease in the solubility with the temperature? ___________
d) Which compound is the most soluble at 40oC? ____________________
e) Name two compounds that have the same value of solubility at a specific temperature.
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