C2.6 Carbon and its Compounds

1. What is the action of heat on carbonates and hydrogen carbonates?

All carbonates except the carbonates of potassium and sodium decompose to produce a metal oxide and carbon (IV) oxide

Ammonium carbonates decompose when heated to produce ammonia, carbon (IV) oxide and water

Hydrogen carbonates decompose on heating to produce a carbonate, carbon (IV) oxide and water

All of the above

2. Which allotrope of carbon has a giant atomic structure in which carbon atom is bonded to four other carbon atoms to form a regular tetrahedron shape?

Silver

Graphite

Diamond

None

3. Allotropy is the existence of an element in more than one form in the same physical state. True or False

FALSE

Maybe

TRUE

None

4. What makes graphite a good conductor of electricity and a good electrode?

It has delocalized electrons in its structure

It has a high melting point and slippery in nature

Because its carbon layers can slide over each other

None of the mentioned

5. Mention the two common allotropes of carbon

Diamond

Silver

Graphite

Both and C

6. Which of the following is not an example of amorphous carbon?

Charcoal

Coal

Coke

Diamond

7. Describe the characteristics of Graphite

Its carbon atom uses only 3 valence electrons to be bonded with 3 carbon atoms

It uses 3 valence electrons in the outermost energy level leaving one electron which is not used in bonding hence having delocalized electron in its structure thus graphite is able to conduct electricity

It has a high melting and boiling point because of the strong covalent bonds between the atoms in the layers

All of the above

8. What is observed when a mixture of carbon and some metals oxides are heated?

Carbon has the ability to remove combined oxygen from some metals hence carbon is oxidized to carbon (IV) oxide and the metal oxides are reduced to metals

Carbon can be placed in the reactivity series of metals between Aluminum and Zinc thus it reduces the oxides of metals below its reactivity series

Carbon is a reducing agent because it reduces metal oxides to metals.

All of the above

9. Name the allotrope of carbon which is black, soft and slippery crystalline solid

Silver

Sodium

Diamond

Graphite

10. Describe the physical properties of Carbon (II) Oxide.

It is colorless, odorless and slightly less dense than air.

It has a low boiling point because of the weak forces of attraction between the molecules

The gas is extremely poisonous it combines with hemoglobin to form stable carboxy-hemoglobin leading to suffocation

All of the above

11. What makes graphite a good lubricant of fast-moving machines which generate a lot of heat?

It has delocalized electrons

It has a high melting point and it’s slippery in nature.

Because its carbon layers can slide over each other

None of the mentioned

12. Carbonates are salts of metal ions or ammonium ions with carbonate ions. True or False

FALSE

Maybe

TRUE

None

13. Mention the properties of Carbon (IV) oxide gas

It is a colorless, odorless gas and denser than air hence collected by downward delivery

It does not support combustion and turns the universal indicator red

When Carbon (IV) oxide is bubbled in Calcium hydroxide a white precipitate is formed to confirm the presence of Carbon (IV) oxide gas

All of the above

14. Explain the products formed when carbonates and hydrogen carbonates react with dilute acids

They form of Salt and Water and Carbon (IV) oxide

The reaction of Calcium carbonate and dilute sulphuric acid does not go to completion due to the formation of insoluble calcium sulphate.

The reaction of Lead carbonate and dilute Sulphuric acid does not go to completion due to the formation of insoluble Lead sulphate

All of the above

15. How does Carbon react with concentrated Nitric (V) acid?

Carbon will act as a reducing agent

Carbon reduces hot concentrated nitric (V) acid to Nitrogen (IV) oxide gas and water

Carbon is oxidized to Carbon (IV) oxide gas

All of the above

16. An impure form of carbon is called

Allotrope

Fullerenes

Amorphous i.e. charcoal

None of the mentioned

17. Describe the characteristics of Diamond

Its carbon uses all the 4 valence electrons to form covalent bonds

It uses all the four electrons in the outermost energy level for bonding hence it lacks any delocalized electrons thus diamond does not conduct electricity

Diamond has a high melting point due to the strong covalent bonds in the structure.

All of the above

18. What is formed when carbon burns in oxygen?

A colorless gas is produced which is Carbon (IV) oxide { C(S) + O2 (g) = CO2 (g) }

It forms a gas that reacts with Calcium hydroxide to form a white precipitate Calcium carbonate and water. { CO2 (g) + Ca(OH)2 (aq) = CaCO3(S) + H2O(l) }

It forms a colorless gas Carbon (IV) oxide which puts out a glowing splint

All of the above

19. Mention the uses of Carbon (IV) oxide

Used as a refrigerating agent for perishable goods since solid carbon (IV) oxide it sublimes when heated leaving no residue

Used in portable fire extinguishers to put out the fire since it doesn’t support combustion

Carbon (IV) oxide is dissolved in water to make aerated drinks to add taste.

All of the above

20. Name the allotrope of carbon which is stable, colorless, transparent and shiny crystalline solid

Silver

Graphite

Diamond

Sodium

21. Which allotrope of carbon has a giant atomic structure in which layers are held together by Van der Waals forces?

Silver

Diamond

Graphite

Sodium

22. How does Carbon react with concentrated sulphuric acid?

Carbon will react as a reducing agent

Carbon reduces hot concentrated Sulphuric acid to Sulphur (IV) oxide and water.

Carbon is oxidized to Carbon (IV) oxide gas

All of the above

23. Describe Carbon (Ii) oxide

Its an oxide of carbon

It is formed by one carbon atom forms 3 covalent bonds with one oxygen atom. C= O

It is a molecular structure

All of the above

24. Fullerene is a synthetic allotrope of carbon. True or False

FALSE

Maybe

TRUE

None

25. Mention the chemical properties of carbon (II) oxide

Carbon (II) Oxide is burned in oxygen to form Carbon (IV) oxide gas

Carbon (II) oxide is a reducing agent to metals low in the reactivity series i.e. copper, lead and iron and in turn it is oxidized to carbon (IV) oxide gas

Carbon (II) oxide burns in air with a blue flame

All of the above

26. How is carbon (IV) oxide prepared in the Lab?

Reacting a metal carbonate and an acid to form salt, water and carbon (IV) oxide gas

Calcium carbonate reacts with an acid to form Calcium Chloride and water and Carbon (IV) oxide gas. { CaCO3 (S) + 2HCl (aq) = CaCl2 (aq) + CO2 (g) + H2O (l) }

Carbon (IV) oxide gas is passed through water to remove traces of hydrochloric acid and then passed through a drying agent anhydrous Calcium Chloride when required dry

All of the above

27. How is Carbon (II) oxide produced in the Lab? By dehydrating Methanoic acid using concentrated Sulphuric (VI) acid?

{ Methanoic acid Conc. Sulphuric acid Carbon(II) oxide + Water }

By dehydrating Ethanedioic acid using concentrated Sulphuric acid {Ethanedioic acid Conc. H2SO4 Carbon (II) Oxide + Water}

Passing Carbon (IV) oxide over heated charcoal {Carbon (IV) Oxide + Carbon 2CO(g) }

All of the above

28. Describe Carbon (IV) oxide gas

It is the most stable oxide of carbon

It’s made up with one carbon atom bonding with two oxygen atom in a strong covalent bond

It is a molecular structure

All of the above

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