F2 IS WS09 Answers

1 Carbon dioxide; oxygen

2 Gaseous exchange; oxygen; carbon dioxide

3 lungs

4 carbon dioxide; oxygen; photosynthesis;

   more; release

   more; net uptake of carbon dioxide

5 respiration; uptake; release

6 constant

7 Greenhouse

8 greenhouse; global warming

1st Term WS 09 Submission date：_____________ Name：______________________ Class & no.：2 _________(     )

7.5       Gaseous exchange between living

             things and the environment

i      Words to know:

	English term	Write the words again	Chinese term
1	Gaseous exchange
2	Lungs
3	Respiration
4	Photosynthesis
5	Greenhouse effect
6	Global warming

i      Fill in the blanks:

1       Breathed air contains more carbon dioxide and less oxygen than unbreathed air.

2        Gaseous exchange occurs continuously between our body and the environment, through which animals (and plants) take in oxygen from air and release carbon dioxide to the environment.

3        In humans, gaseous exchange occurs inside the         lungs.

4        During daytime, green plants consume carbon dioxide and produce oxygen in photosynthesis. In other words, green plants carry out photosynthesis at a faster rate than respiration.

           Amount of oxygen produced in photosynthesis                     more         than Amount6 of oxygen absorbed in respiration

          Therefore, it has a net release of carbon dioxide.

          Amount of carbon dioxide absorbed for photosynthesis      more          than amount of carbon dioxide produced in respiration

          Therefore, it has a net uptake of carbon dioxide

5       At night, photosynthesis stops but respiration goes on in green plants. Therefore, they have net uptake of oxygen and release of carbon dioxide.

6       The contents of oxygen and carbon dioxide in nature are kept more or less constant. This is known as the balance of oxygen and carbon dioxide in nature.

7       Greenhouse effect is the phenomenon that carbon dioxide (and some other gases) in

           the atmosphere traps some of the heat from the Sun and keeps the Earth warm.

8       The increasing amounts of carbon dioxide in the atmosphere lead to an excessive greenhouse   effect and hence global warming.

F2 IS QZ 04 ans

7.3

Word Translation (6 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	化學能	Chemical energy
2	能量值	Energy content
3	千卡路里	Kilocalories
4	千焦耳	Kilojoules
5	過重	Overweight
6	呼吸作用	Respiration

Fill in the Blanks (22 marks)

1      We need energy to carry out various activities. Energy is also needed for maintaining our body temperature, heartbeat and breathing. Such energy comes from the food we eat.

2      In our body, the chemical energy stored in food is released by a complex chemical process called respiration. It takes place in our living cells.

3      In respiration, food reacts with oxygen to form carbon dioxide and water. The energy released is used to support our body activities.

4      Write down the word equation of respiration.

        Food + oxygen -------------------------------à energy + carbon dioxide + water

5      In both burning and respiration, oxygen is consumed and carbon dioxide and water are produced. Energy is released faster in burning than in respiration.

6      The amounts of energy that the foods can provide are called the energy content.
It is measured in kilojoules (kJ) or kilocalories (kcal).

7      Eating too much high-energy food can make us become overweight.

Challenging Questions (Bonus 2 marks)

List TWO differences between respiration and burning.

A flame exists in burning but not in respiration. /

Respiration is a much more complicated process than burning. /

Respiration occurs in living cells while burning takes place in living cells. /

The energy is released much slower in respiration than burning. (Any TWO)

F2 IS QZ 03 ans

7.2AB

Word Translation (9 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	發生反應	React
2	燃料	Fuel
3	氧	Oxygen
4	火三角	Fire triangle
5	必須條件	Necessary condition
6	燃料	Fuel
7	氧	Oxygen
8	高溫	High temperature
9	熄滅	Go out

Fill in the Blanks (16 marks)

1      Burning is a chemical process involving fuel and oxygen.

2      When fuels burn in air, they react with oxygen and produce carbon dioxide

and water. Light / heat energy and heat / light energy are given out.

3      The word equation of burning is:

                Fuel + oxygen --------------------------------------------à carbon dioxide + water + energy

4      Fuel, oxygen and a sufficiently high temperature are necessary conditions of

burning. They form the fire triangle. If any one of them is removed, the

fire will go out.

5      When a fire breaks out, we should:

- keep calm;

- leave the flat using stairway and must not use the lift;

- call the Fire Services Department by dialing ‘999’ when you are safe.

Challenging Questions (Bonus 2 marks)

How can we test for the products of burning? Describe the test results.

We can use hydrogencarbonate indicator (lime water) to test for carbon dioxide. The colour changes from red to yellow (changes from colourless to milky).

We can use dry cobalt chloride paper to test for water. The colour changes from blue to pink.

F2 IS QZ 02 ans

7.1BC

Word Translation (7 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	燃燒中的木條	Burning splint
2	帶星火的木條	Glowing splint
3	碳酸氫鹽指示劑	Hydrogencarbonate indicator
4	石灰水	Lime water
5	氯化鈷試紙	Cobalt chloride paper
6	未經呼吸的空氣	Unbreathed air
7	呼出的空氣	Breathed air

Fill in the Blanks (10 marks)

1      Oxygen can be tested by burning splint which burns more brightly in

oxygen. Oxygen can also relight a glowing splint.

2      We can use lime water to test for carbon dioxide. Its colour changes from

colourless to milky. We can also use hydrogencarbonate indicator to

test for it. Its colour changes from red to yellow in carbon dioxide.

3      Water can turn dry cobalt chloride paper from blue to pink.

4      Unbreathed air contains more oxygen but less carbon dioxide while

        breathed air contains less oxygen and more carbon dioxide.

Challenging Questions (Bonus 3 marks)

Give THREE differences between unbreathed air and breathed air.

The unbreathed air contains more oxygen, less carbon dioxide and less water vapour

than breathed air