Page 67 - 新思维科学学生用书7 样章

2 Materials and their structure water oxygen nitrogen carbon dioxide

carbon dioxide

nitrogen

oxygen

water
Air is a mixture of several elements and compounds.

Questions

The diagram shows some particles in air. The red circles represent oxygen atoms. The black circles
represent carbon atoms. The blue circles represent nitrogen atoms. The white circles represent
hydrogen atoms.
1 Which is the most common element in air?

2 How many different kinds of substance are shown in the diagram?
3 Which is the least common compound in this sample of air?

TYPICAL ANALYSIS mg/l
Mineral water is a mixture CALCIUM 55

MAGNESIUM 19
The label on a bottle of mineral water lists many minerals. POTASSIUM 1
There is more than just water in the bottle. The bottle contains SODIUM 24

a mixture of water and other substances. BICARBONATE 248
CHLORIDE 37
The minerals are dissolved in the water. The mineral water is a SULPHATE 13
solution. A litre of water may have about of minerals dissolved NITRATE < 0.1
in it. IRON 0
ALUMINIUM 0
Question DRY RESIDUE AT 180°C 280
4 Look at the picture of a mineral water label. pH AT SOURCE 7.4

List the three most abundant minerals in this bottle of The label shows the minerals found in
mineral water. mineral water.

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