F2 Worksheet 10.4 answers

10.2            Acids and corrosion

I.    Words to know:

	English term	Write the words again	Chinese term
1	Hydrogen	Hydrogen	氫
2	Corrosive	Corrosive	腐蝕性
3	‘pop’ sound	‘pop’ sound	爆鳴聲
4	Marble	Marble	大理石
5	Limestone	Limestone	石灰石
6	Calcium carbonate	Calcium carbonate	碳酸鈣

II.   Fill in the blanks:

1.     Corrosive effects of acids on metals

Ø   Some metals (e.g. zinc and magnesium) react with dilute acids. During the reactions, (1) hydrogen gas and heat are produced. The metals decrease in size gradually. Thus acids have (2) corrosive effects on these metals.

²  Test for hydrogen:
Put a burning splint near the mouth of a test tube containing the gas. If the gas is hydrogen, it burns with a (3) “pop” sound.

2.     Corrosive effects of acids on building materials

Ø   Both (4) marble and (5) limestone are easily corroded by acids. This is because they contain (6) calcium carbonate, which reacts quickly with dilute acids to give off (7)carbon dioxide.