OXIDES AND CARBON

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Afzala janpati biraul Darbhanga, City br

NEW TRENDS IN ICSE CHEMISTRY - 8

CHAPTER - 10. Oxides and Carbon

Tick (✔) The correct choice amongest the following

1. Give the formula of baking soda :(a) Na2CO3(b) NaHCO3(c) CH3COOH(d) NaCO3

2. The process by which food is oxidised :(a) Photosynthesis(b) Carbonation(c) Respiration(d) Tongs

3. A solution used in testing carbon dioxide(a) Lime water(b) Lime juice(c) Lime(d) Milk of lime

4. Which acid is present in vinegar ?(a) Boric acid(b) Acetic acid(c) Carbonic acid(d) Ferric acid

5. Solidified carbon dioxide is known as :(a) Dry ice(b) Wet ice(c) Solidifiedice(d) None of these

Fill in The Blanks

1. Carbon dioxide is collected by .................... displacement of air.

2. .................... layer absorbs ultraviolet radiations.

3. .................... and .................... gases contribute to the greenhouse effect.

4. Dry ice is used in food .................... .

5. Photosynthesis release .................... gas.

Write True or False for each statment.Rewrite the Statement Correctly

1. Carbon dioxide is a supporter of combustion.

2. A clear solution of Ca(OH)2 is known as lime water.

3. Dry ice produces very low temperature of about - 40°C.

4. Dry ice does not sublime.

5. Carbon dioxide helps in respiration.

Match The Columns

1. 1.Aerated drinks2.Photosynthesis3.Respiration4.Fixed air Carbon dioxideRequires carbon dioxideReleases carbon dioxideFizziness

Give one Word for The Followings

1. When leaves mature and fall off very soon ..................... .

2. The complex formed by binding carbon monoxide with haemoglobin ..................... .

3. The gas released during incomplete combustion ..................... .

4. The furnace which is used to prepare iron ..................... .

5. The suffocation caused due to lack of oxygen ..................... .

Answer The Followings Questions

1. What is the extent of carbon dioxide in free air ?

2. What are calcareous shells made-up of ?

3. What is the method of collection of carbon dioxide ?

4. Which gas is released during the process of photosynthesis ?

5. How many colours are present in the visible component of light ?

6. Define infra red radiations.

7. Why carbon dioxide gas is used as a fire extinguisher ?

8. Give two reasons why carbon dioxide is collected by the upward displacement.

9. Why sulphuric acid is not used for preparation of carbon dioxide ?

10. Explain why carbon dioxide is used as fire extinguisher.

11. Explain why carbon dioxide is used in aerated drinks.

12. What is greenhouse effect? How has global warming led to melting of ice caps ?

13. Give tests for carbon dioxide.

14. Explain and give significance of photosynthesis

Answers

Tick (✔) The correct choice amongest the following

1. (b) NaHCO3

2. (c) Respiration

3. (a) Lime water

4. (b) Acetic acid

5. (a) Dry ice

Fill in The Blanks

1. upward

2. Ozone

3. Carbon dioxide, methane

4. preservation

5. oxygen

Write True or False for each statment.Rewrite the Statement Correctly

1. False (Carbon dioxide is a non-supporter of combustion.)

2. True

3. True

4. False (Dry ice is sublimable.)

5. False (Carbon dioxide helps in photosynthesis.)

Match The Columns

1. 1.Fizziness

2.Requires carbon dioxide

3.Releases carbon dioxide

4.Carbon dioxide

Give one Word for The Followings

1. Premature ageing

2. Carboxy haemoglobin

3. Carbon monoxide

4. Blast fumance

5. Asphyxia

Answer The Followings Questions

1. 0.02 - 0.04 %

2. Calcium carbonate

3. Upward displacement of air

4. Oxygen

5. Seven (violet, indigo, blue, green, yellow, orange and red)

6. Infra red radiations : These radiations are actually the heat radiations which possess sufficient energy to cross the atmosphere and heat the surface of earth.

7. Firstly, it is a non-supporter of combustion. Secondly, being heavier than air it forms a blanket on the surface of fire and cuts off the oxygen supply due to which the fire gets extinguished.

8. The gas is collected by upward displacement of air because :

1. It is heavier than air.

2. It is soluble in water.

9. Because sulphuric acid forms an insoluble layer of sulphate which stops the further reaction from taking place.

10. Most of the fire extinguishers in their chemical reactions generate carbon dioxide gas. This gas actually helps to extinguish fire because of two reasons.

Firstly, it is a non-supporter of combustion. Secondly, being heavier than air it forms a blanket on the surface of fire and cuts off the oxygen supply due to which the fire gets extinguished.

11. Carbon dioxide gas dissolves rapidly under pressure. It gets dissolved in sugar solutions containing different flavours. These soft drinks are some time called fizzy drinks.

12. The heating of the earth and atmosphere due to infra red radiations trapped by the carbon dioxide layer, is called the greenhouse effect.

The gases contributing to greenhouse effect are carbon dioxide, methane and water vapours.

Due to the increase in the concentration of green house gases, the temperature of the earth rises. This is called global warming. It increases the temperature of earth leading to the melting of polar ice caps which further leads to the submergence of low lying areas under water.

13. (i) Carbon dioxide turns lime water milky.

(ii) It extinguishes the fire and hence acts as fire extinguisher.

14. Green plants contain chlorophyll which traps solar energy and binds carbon dioxide of air and water in the form of carbohydrates by a process known as photosynthesis.

This process is a vital process for human beings and animals because It generates food for humans and animals. It releases life supporting oxygen gas.