Chapter 8

Question 1

What are hydrocarbons?

Answer 1

Compounds of hydrogen and carbon.

Question 2

What are homologous series?

Answer 2

Hydrocarbons of similar properties are placed into series that differ by CH2.

Question 3

What is the general formula for alkanes and why are they saturated?

Answer 3

Formula: CnH2n+2.

Because they contain all single bonds.

Question 4

What is the general formula for alkenes and why are they unsaturated?

Answer 4

Formula: CnH2n

Because they contain a carbon-carbon double bond.

Question 5

What is the general formula for alkynes and why are they unsaturated?

Answer 5

Formula: CnH2n-2

Because they contain a carbon-carbon triple bond.

Question 6

What are structural isomers?

Answer 6

Molecules with the same molecular formula but different structure.

Question 7

What does a semi-structural formula show?

Answer 7

The order in which carbon atoms are attached to the carbons in a molecule.

Question 8

What is the process of naming carbon compounds?

Answer 8

You must look for the longest unbranched chain, then number the carbon atoms from end to end of the chain that will give the smallest numbers to double bonded carbons and to branching chains.

Question 9

How are alkyl groups named?

Answer 9

After the alkane from which they are formed.

Question 10

How is the position of the double bond identified?

Answer 10

By the number of the first carbon atom involved in the bond and its presence by the suffix Rene.

Question 11

Describe hydrocarbons in terms of the strength of molecular bonds

Answer 11

Non-polar with strong covalent bonds within the molecule and weak dispersion forces between hydrocarbon chains.

Question 12

Where is the number and position of each of the alkyl groups found?

Answer 12

At the beginning of the compound’s name.

Question 13

What properties of a hydrocarbon are changed as the size of the molecule increases?

Answer 13

The boiling point and viscosity increases, the volatility decreases.

Question 14

What is the most common reaction of alkanes?

Answer 14

Their combustion in oxygen to release heat, producing carbon dioxide and water also.

Question 15

What are typical reactions of alkenes called?

Answer 15

Addition reactions, where 2 reactant molecules become one.

Question 16

What are polymers?

Answer 16

Very large covalent molecules made up of repeating units called monomers.

Question 17

What do alkenes form?

Answer 17

Polymers.

Question 18

What is the name of a polymer that can be heated and reshaped?

Answer 18

A thermoplastic polymer.

Question 19

Is polyethene a thermoplastic polymer?

Answer 19

Yes.

Question 20

What effects the physical properties of polymers?

Answer 20

The degree of branching, the nature of the side of groups, the arrangement of the side-groups and the amount of cross-linking.

Question 21

What properties does the degree of branching lower in polymers?

Answer 21

The density, hardness and melting point of the polymer.

Question 22

What are the properties of thermosetting polymers?

Answer 22

They have extensive cross-linking and cannot be reheated and reshaped, they char and burn when heated, and they contain covalent bonds between the chains as well as in the chains forming a covalent lattice.

Question 23

What are estomers and what are their properties?

Answer 23

Polymers that can be stretched or pulled out of shape and then will return to their original shape. They contain covalent bonds between the chains but fewer than in thermosetting polymers, and burn and char when heated.