Year 8 Science · Unit 2 · Lesson 18
Foundation Worksheet
Learning Goals
True or False? Fix the false ones
Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.
Table salt (NaCl) is safe to eat even though sodium and chlorine are both individually dangerous substances.
Correct it:
The properties of a compound can always be predicted by knowing what elements it contains.
Correct it:
Water is flammable because it contains hydrogen, which is a highly flammable gas.
Correct it:
Iron oxide (rust) is magnetic, just like iron metal.
Correct it:
Carbon dioxide is used in fire extinguishers because it is a heavy, non-flammable gas that smothers flames.
Correct it:
Match each compound to its use
Draw a line connecting each compound on the left to its correct use on the right. Or write the matching letter next to each compound.
| Compound | Your answer | Use |
|---|---|---|
| NaCl (sodium chloride) | A. Manufactured into glass for windows and screens. | |
| H₂O (water) | B. Used as a red and orange pigment in paints and coatings. | |
| CO₂ (carbon dioxide) | C. Food flavouring and preservation; road de-icing in winter. | |
| Fe₂O₃ (iron oxide) | D. Universal solvent; essential for all living things. | |
| CaCO₃ (calcium carbonate) | E. Fire extinguisher gas; carbonates fizzy drinks. | |
| SiO₂ (silicon dioxide) | F. Building material in limestone, chalk, and cement. |
1. Name two compounds from this lesson and state one property of each compound that is completely different from any of its constituent elements.
2. Sodium is a reactive metal and chlorine is a toxic gas. Explain in your own words why it is safe to put sodium chloride (table salt) on your food.
Wrap Up
In one sentence, what was the main idea of this lesson?