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10.4 Acids and
corrosion
i Words to know:
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English term
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Write the words again
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Chinese term
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1
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Corrode
(vb)
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腐蝕 (動詞)
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2
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Corrosion
(n)
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腐蝕 (名詞)
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3
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Corrosive
(adj)
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腐蝕性的 (形容詞)
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4
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‘Pop’
sound
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爆鳴聲
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5
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Hydrogen
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氫
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6
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Marble
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大理石
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7
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Limestone
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石灰石
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8
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Calcium
carbonate
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碳酸鈣
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i Fill in the blanks:
1 Some metals (e.g. zinc and magnesium) react with dilute acids. During
the reactions,
hydrogen gas and heat are produced. The
metals decrease in size gradually.
Thus acids have corrosive effects on these metals.
2 To test for hydrogen, a burning splint is put near the mouth of the test
tube containing the gas.
It
burns with a ‘pop’ sound if the gas is hydrogen.
3 The reactivity of the metals (zinc, magnesium, copper and iron) with
acid in descending order is:
Magnesium
> zinc > iron > copper
4 Dilute acids react with calcium
carbonate to
give off carbon dioxide.
5 Some building materials such as marble
and limestone contain calcium carbonate.
They are easily corroded by acids. The reaction gives out carbon dioxide
which turns limewater milky.
Hydrogen burning splint
'pop' sound
Calcium carbonate milky
i Multiple Choice: Circle
the letter of the best answer for each question.
1. When zinc beads are added to dilute hydrochloric acid, gas
bubbles are given out.
The gas can
A. relight a glowing splint.
B. turn hydrogencarbonate indicator yellow.
C. give a
‘pop’ sound with a burning splint.
D. turn lime water milky.
2. Which of the following metals react(s) with dilute acids?
(I) Zinc (II) Magnesium (III) Copper
A. (I) only B. (I)
and (II) only C. (II) and (III) only D. (I), (II) and (III)
3. Which of the following metals reacts the
most vigorously with dilute hydrochloric acid?
A. Zinc B. Magnesium C. Copper D. Iron
4. Which of the following
is the gas given off when limestone pieces are added to dilute hydrochloric
acid?
A. Hydrogen
B. Oxygen
C. Chlorine
D. Carbon
dioxide
i Concept checking: Decide whether the following
statements are true or false, and try to rewrite the true statements.
1 Metal
saucepans should not be used to cook ‘pork trotters in vinegar sauce’. True / False
_____________________________________________________________________________
2 Hydrogen
gas will be given off when marble pieces are added into dilute True / False
hydrochloric acid.
Carbon
dioxide will be given off when marble pieces are added into dilute hydrochloric
acid /
Hydrogen
gas will be given off when metals (magnesium or zinc) are added into dilute
hydrochloric acid
3 Heat is
produced when a copper strip is put in dilute hydrochloric acid. True
/ False
Heat is
produced when a magnesium / zince strip is put in dilute hydrochloric acid
4 Zinc
decreases in size gradually in a dilute acid, but limestone does not. True
/ False
Both
zinc and limestone decrease in size gradually in a dilute acid
5 When a piece of eggshell is
immersed in vinegar, the gas produced can turn lime True / False
water milky.
_____________________________________________________________________________
i Skill development – Different forms of words: Fill in the blanks with the following
words.
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corrosion corrosive corrode corroded
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1. Acids can corrode some metals.
2. Acids have corrosive effect on some metals.
3. Some metals are corroded by acids.
4. Acids can cause corrosion of some metals.
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