Graphite

Q. Ice float on water. Which hydrogen bond is responsible for this? Intermolecular hydrogen bond or intramolecular hydrogen bond.

Q.

Answer the following questions :

(a) Why is graphite a good conductor of electricity but not diamond ?

(b) Why is diamond very hard ?

(c) What are fullerenes ? Name the most common fullerene.

(d) What impurity is present in black diamond ?

Q.

Why does water molecules attract each other?

1. None of these

2. Oxygen - oxygen (neighboring molecule)

3. Hydrogen - oxygen bonding

4. Hydrogen - hydrogen bonding

Q.

Bond formation occurs when the energy of the system

1. decreases

2. increases

3. remains same

Q.

Which of the following is a good conductor of electricity: (a) diamond (b) graphite

Q.

Write 'true' or 'false' against the following statements :

(a) Carbon constitutes 0.03$\%$ of the earth's crust.

(b) Graphite is the purest form of carbon.

(c) Coloured diamonds are costlier than colourless and transparent diamonds.

(d) Graphite has layers of hexagonal carbon bondings.

(e) Diamond is insoluble in all solvents.

Q.

Name an allotrope of carbon which contains both single and double bonds between carbon atoms.

1. Graphite

2. Diamond

3. Fullerene

4. No allotrope meets such a condition

Q.

Graphite is a soft lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite

1. has Carbon atoms arranged in flat parallel layers of rings of strongly bound Carbon atoms with weak interlayer bonds.

2. is a noncrystalline substance

3. is an allotropic form of Carbon.

4. has the only a single bond between Carbon atoms.

Q.

Why is energy released when new bonds are formedin a chemical reaction?

Q.

What is the major content of lead pencil?

1. PbS

2. Graphite

3. FeS

4. Pb

Q.

The weak attractive forces that act on neutral atoms and molecules of the same type are collectively known as _____

1. Covalent bonding

2. Hydrogen bonding

3. Van der Waals forces

4. Electrostatic forces of attraction

Q.

___ allotrope of carbon acts as a lubricant at high temperatures.

Q.

Ishita wanted to select one of the allotropic forms of carbon as a lubricant for fast moving machinery parts. Which material should she use and why?

(Hint: Recall the structure and uses of crystalline forms of carbon.)

Q.

Diamond is made up of flat planar layers of $\mathrm{Carbon}$ atoms.

1. True
2. False

Q. ___ acts as a lubricant at higher temperatures.

Q.

Which allotrope of carbon is also called a solid lubricant?

1. Diamond

2. Lampblack

3. Graphite

4. Coal

Q.

C-C bond length is maximum in ___ .

1. diamond

2. graphite

3. naphthalene

4. fullerene

Q. Why is diamond called nonmetal?

Q.

Is graphite also a allotrope of carbon?

Q.

Which of the given options has free electrons and can conduct electricity?

1. Diamond

2. Graphite

3. Wood

4. Rubber

Q. Choose the correct option regarding the statements given below:

Statement 1 : Graphite is used in dry cells that are present in electric motors.
Statement 2 : Graphite is a bad conductor of electricity.

1. Statement 1 and statement 2 are true.
2. Statement 1 and statement 2 are false.
3. Statement 1 is true but statement 2 is false.
4. Statement 1 is false but statement is true.

Q. A non-metal $X$ exists in two different forms $Y$ and $Z$. $Y$ is the hardest natural substance whereas $Z$ is a good conductor of electricity. $Y$ is :

1. graphite
2. carbon
3. diamond
4. none of the above

Q.

Graphite is a non-metal and has very low melting and boiling points.

1. True

2. False

Q. The weak attractive forces that act on neutral atoms and molecules of same type are collectively known as

1. Electrostatic forces of attraction
2. Covalent bonding
3. Hydrogen bonding
4. Van der Waals forces

Q.

With respect to diamond and graphite, which of the statement(s) given below is/are correct?

1. Graphite is harder than diamond.

2. Graphite has higher electrical conductivity than diamond

3. Graphite has higher thermal conducitivity than diamond.

4. Graphite has higher C - C bond order than diamond

Q. If X is a non-metal. It will not conduct electricity unless it is carbon in the form of :

1. None of these
2. Diamond
3. Fullerene
4. Graphite

Q.

The incorrect statement related to allotropes of carbon is/are

1. Diamond is the hardest allotrope of carbon and having a three dimensional network structure of

2. Electrostatic force of attraction acts between the layers of graphite 6.14 Å away from each other

3. Graphite is the most stable allotropes of carbon and having a two dimensional sheet like structure of hexagonal rings of carbon

4. Fullerene (C60) is recently discovered non-crystalline allotrope of carbon having a football-like structure

Q.

What are the effects or uses of buckminsterfullerene ?

Q.

explain different types of van der wall forces ??

Q. PVC have more intermolecular force of attraction than natural rubber?