Class-8th Carbon Essential ICSE Chemistry Ch-9 Solutions Bharti Bhawan Publishers. We Provide Step by Step Answer of Objective, True False , Match the Following, Short / Long Answer Type of Exercise / Lesson -9 Carbon . Visit official Website CISCE for detail information about ICSE Board Class-8.
ICSE Chemistry Ch-9 Solutions Class-8th Carbon Essential
| Board | ICSE |
| Publications | Bharti Bhawan |
| Subject | Chemistry |
| Class | 8th |
| Chapter-9 | Carbon |
| Book Name | Essential |
| Topics | Solution of Objective, True False , Match the following, Fill in the blanks , Short / Long Answer Type Questions |
| Academic Session | 2021-2022 |
Short-Answer Type Questions
(Class-8th Carbon Essential ICSE Chemistry Ch-9 Solutions Bharti Bhawan Publishers)
Page 109
Question 1:
Name any three sources of carbon in which it exists in the free state.
Answer : Coal. Diamond. Graphite.
Question 2:
Name three inorganic compounds containing carbon. Name any three organic compounds
Answer : Some simple compounds that contain carbon are often considered inorganic. Examples include carbon monoxide, carbon dioxide, carbides,
three organic compounds-Fat, carbohydrate, Glucose
Question 3:
What are the following called?
(i) Solids which have definite geometrical forms
(ii) Solids which do not have definite geometrical forms
Give any two examples of each type.
Answer :
(i) crystals.—
(ii) An amorphous solid-
Question 4:
Define allotropy. Name any two elements which exhibit this phenomenon
Answer :The term allotrope refers to one or more physical forms of a chemical element that occurs in the same physical state. Allotropes may show differences in chemical and physical properties.
Carbon Allotropes–Diamond, Graphite, Fullerene
Question 5:
Show the allotropy of carbon with the help of a chart
Answer : Carbon is capable of forming many allotropes due to its valency. Well-known forms of carbon include diamond and graphite. In recent decades many more allotropes and forms of carbon have been discovered and researched including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures
Question 6:
Which property of diamond makes it sparkle?
Answer : Only a portion of the light hitting a diamond is reflected; the rest travels through it. As the light moves through the diamond, it is scattered and fractured, creating the sparkle that diamonds are known for. This is the refraction
Question 7:
What does destructive distillation mean?
Answer : The heating of a material, such as coal or wood, in an inert atmosphere, at a high temperature such as to cause decomposition; the principal products include oils and tars from which many useful organic compounds may be obtained; town gas and coke were obtained in this way
Question 8:
What is activated charcoal?
Answer : Activated charcoal is created when organic materials, such as wood, are burned at extremely high temperatures in environments lacking oxygen. This process causes the materials to develop a large number of pores. This porous quality is what is said to make activated charcoal useful in absorbing toxins and clearing the body of unwanted substances
Question 9:
Define adsorption and give an example
Answer :The accumulation of the molecular species at the surface rather than in the bulk of a solid or liquid is known as adsorption. For example, water vapour are adsorbed by silica gel.
Question 10:
Which property of carbon makes it useful in metallurgy?
Answer :Generally, carbon is the most important commercial steel alloy. Increasing carbon content increases hardness and strength and improves hardenability. But carbon also increases brittleness and reduces weldability because of its tendency to form martensite
Question 11:
Which gas is evolved when a metal carbonate is treated with an acid?
Answer : Acids react with metal carbonates or metal bicarbonates to give out carbon dioxide, along with the corresponding metal salts and water.
Question 12:
Name a solution that turns milky on reacting with CO2 .
Answer : Lime water
Question 13:
Name the gas formed by the incomplete combustion of carbon.
Answer : carbon monoxide
Question 14:
Which compound is formed when CO reacts with hemoglobin?
Answer : carboxyhemoglobin
Question 15:
What do the abbreviations CNG and LPG stand for?
Answer : CNG stands for ‘compressed natural gas’, and LPG stands for ‘liquefied petroleum gas
Question 16:
Name a greenhouse gas present in air.
Answer :The primary greenhouse gases in Earth’s atmosphere are water vapor (H 2O), carbon dioxide ( CO 2), methane ( CH 4), nitrous oxide ( N 2O), and ozone (O3).
Long-Answer Type Questions
(Class-8th Carbon Essential ICSE Chemistry Ch-9 Solutions Bharti Bhawan Publishers)
Page 110
Question 1:
Describe two distinguishing characteristics of crystalline and amorphous solids.
Answer :
| Crystalline solids | Amorphous solids |
|---|---|
| They are true solids. | They are pseudo solids or super cooled liquids. |
| They have sharp melting points. | They do not have sharp melting points. |
| They are anisotropic in nature. | They are isotropic in nature. |
| They have definite heat of fusion. | They do not have definite heat of fusion. |
Question 2:
Show how the destructive distillation of wood can be carried out on a small scale. What are the products formed?
Answer :the decomposition of wood by heating to a temperature of 450°–550°C in the absence of air. The products of this process are gases (carbon dioxide, carbon monoxide, methane), liquids, and a solid residue —charcoal. The distillate, in turn, separates into pyro-ligneous acid and wood tar
Question 3:
Describe the preparations of lampblack, coke and gas carbon.
Answer :
The process of heating coal in the absence of air is called the destructive distillation of coal. Coal contains a number of elements such as carbon, hydrogen, oxygen, nitrogen and sulphur. When coal is heated in the absence of air, a number of products are obtained. Products obtained from the destructive distillation of coal are
- Coke: contains 98 % carbon. It is porous, tough, black and the purest form of coal. Like charcoal, it is a good fuel and burns without smoke.
- Coal tar (liquid): Coal tar is a mixture of different carbon compounds. Its thick, black liquid with unpleasant smell. The fractional distillation of coal tar gives many chemical substances which are used in the preparation of dyes, explosives, paints, synthetics fibers, drugs, and pesticides.
- Coal Gas: Coal gas is mainly a mixture of hydrogen, methane and carbon monoxide. The gases present in coal gas are combustible and hence, it is an excellent fuel.
Question 4:
Describe the laboratory preparation of carbon dioxide.
Answer : Carbon dioxide is produced whenever an acid reacts with a carbonate. This makes carbon dioxide easy to make in the laboratory. Calcium carbonate and hydrochloric acid are usually used because they are cheap and easy to obtain. Carbon dioxide can be collected over water, as shown in the diagram.
Question 5:
Explain how carbon monoxide acts as a poison and how an affected person should be treated.
Answer : When too much carbon monoxide is in the air you’re breathing, your body replaces the oxygen in your red blood cells with carbon monoxide. This prevents oxygen from reaching your tissues and organs.
Exercise Objective Type Questions
(Solutions of Bharti Bhawan Publishers Chemistry ICSE Class-8th Essential Chemistry Ch-9 Carbon)
Page 110
Choose the correct option.
1. which of the following is an amorphous or a microcrystalline form of carbon ?
(a) Graphite
(b) Fullerene
(c) Diamond
(d) Coke
Answer : (d) Coke
2. Which of the following conditions are required for the formation of diamond ?
(a) Very high temperature and pressure
(b) Very high temperature, but a very low pressure
(c) Very low temperature, but a very high pressure
(d) Very low temperature and pressure
Answer : (a) Very high temperature and pressure
3. What is the lead’ of a pencil made of?
(a) Clay
(b) Graphite
(c) A mixture of clay and graphite
(d) Lead metal
Answer : (b) Graphite
4. Which of the following will give carbon dioxide on being heated in an excess of oxygen?
(a) Diamond
(b) Graphite
(c) Charcoal
(d) All of these
Answer : (d) All of these
5. Which among the following has the largest surface area?
(a) Diamond
(b) Wood charcoal
(c) Graphite
(d) Activated charcoal
Answer :(d) Activated charcoal
6. Which of the following is water gas?
(a) Air dissolved in water
(b) Water vapour present in air
(c) A mixture of CO and H2
(d) A mixture of CO and H2O (steam)
Answer : (d) A mixture of CO and H2O (steam)
7. Which of the following is the best option for cooking fuel?
(a) Wood
(b) Cow-dung cake
(c) LPG
(d) Kerosene
Answer : (c) LPG
8. which of the following steps will lead to a decrease in CO2 level in air?
(a) Afforestation
(b) Deforestation
(c) Replacing LPG by coal in the kitchen
(d) Increased use of wood as domestic fuel.
Answer : (a) Afforestation
Match columns A and B.
Question-1.
| A | B |
| (i) Activated charcoal | (a) amorphous |
| (ii) Diamond | (b) layered, hexagonal rings |
| (iii) Gas carbon | (c) best adsorbent among the alltropes of carbon |
| (iv) Graphite | (d) each carbon atom tetrahedrally bonded too four others |
Answer :
| A | B |
| (i) Activated charcoal | (a) amorphous |
| (ii) Diamond | (b) layered, hexagonal rings |
| (iii) Gas carbon | (c) best adsorbent among the allotropes of carbon |
| (iv) Graphite | (d) each carbon atom tetrahedrally bonded too four others |
Question -2.
| A | B |
| (i) Colorless diamond | (a) lubricant |
| (ii) Black diamond | (b) gas mask |
| (iii) Graphite | (c) rock drilling |
| (iv) Wood charcoal | (d) jewellery |
| (v) Bone charcoal | (e) printers ink |
| (vi) Lampblack | (f) refining Sugar |
Answer-
…………………
Question- 3.
| A | B |
| (i) Carbon | (a) turns limewater milky |
| (ii) Carbon monoxide | (b) cracking of petroleum |
| (iii) Carbon dioxide | (c) has many allotropes |
| (iv) LPG | (d) forms carboxyhaemoglobin |
Answer :
…………………………….
Fill in the blanks.
1. Charcoal is prepared by the .…..destructive….. distillation of wood, bone or sugar. (fractional/destructive)
2 Gas carbon is a ….good……. Conductor of electricity. (good/ bad)
3. Charcoals are good …..adsorbents... (adsorbents/absorbents)
4. In the dark, chlorine adsorbed on charcoal reacts with hydrogen more ..reluctantly.……. than chlorine ordinarily mixed with hydrogen. (readily/reluctantly)
5. Water gas is formed when …..steam……. passed over ….red-hot…. coke. (water/steam/red-hot/cold)
6. Complete the following chemical equations and balance them.
(a) CO + O2 —> …….
(b) ZnO + C –> ……. + …..
(c) FeO3 + …… —> ….. + CO
(d) Sn2O2 + ….. —> ….. + CO
(e) PbO + C —> … + …..
(f) MgO + CO2 —> …. + ….
(g) Na2CO3 + HCl —> …. + …… + 2Nacl
Ans
(a) CO + O2 —> 2CO + O 2 → CO 2
(b) ZnO + C –> Zn + CO
(c) FeO3 + 3CO → Fe + 3CO2
(d) Sn2O2 + 2C → 2CO + 2Sn
(e) 2PbO + C → 2Pb + CO2
(g) Na2CO3(aq)+2HCl(aq)→2NaCl(aq)+CO2(g)+H2O(l)
Write ‘T’ for true and ‘F’ for false for the following statements
1. Carbon is not found in the free state in nature F
2. Diamond is the hardest substance known T
3. Being a nonmetal, graphite is a bad conductor of electricity F
4. Charcoal is used in the purification of water. F
5. A component of water gas is used in the manufacture of ammonia T
6. One gets asphyxiated in an atmosphere of CO. T
7. CNG is a cleaner fuel than petrol T
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