Chemistry B L10: Hydrocarbons

What type of bonding is found in hydrocarbons?

• hydrogen

• polar

•  

  ionic

• covalent

Answer explanation

The bonding in hydrocarbons is covalent. 

What are substances with benzene type rings called?

• isomers

• aliphatic compounds

• aromatic compounds

• cycloalkanes

Answer explanation

Substance containing benzene type rings are called aromatic compounds.

A hydrocarbon is an organic molecule composed entirely of what elements?

• hydrogen and carbon

• hydrogen, carbon, and helium

• hydrogen, carbon and oxygen

• oxygen and carbon

Answer explanation

A hydrocarbon is an organic compound that contains only carbon and hydrogen.

Complete this sentence.  As the number of carbon atoms in a formula _____, the number of possible isomers _____.

• decreases, increases

• increases, decreases

• decreases, decreases

• increases, increases

Answer explanation

As the number of carbon atoms in a formula increases, the number of possible isomers increases.

What is the name of this compound?

• butene

• 1-methylpropane

• butane

• methylpropene

Answer explanation

The molecule is a straight-chain alkane of four carbons called butane. 

What property determines the different fractions during the distillation of petroleum?

• reactivity

• molar mass

• boiling point

• hydrogen saturation

Answer explanation

Petroleum refining begins with the distillation of crude oil into fractions according to boiling point. 

Which of the following is a constitutional isomer of 2-pentene (CH₃CH₂CH=CHCH₃)?

• CH₃CH₂CH=CHCH₂CH₃

• CH₃CH₂CH₂CH=CH₂

• CH₃CH₂CH₂CH₂CH₃

• CH₃CH=CHCH₃

Answer explanation

2-pentene consists of 5 carbon atoms and 10 hydrogen atoms with a double bond between the second and third carbons in the chain. CH₃CH₂CH=CHCH₂CH₃ has 6 carbons and 12 hydrogens. CH₃CH₂CH₂CH=CH₂ (1-pentene) is the only other molecule with this same chemical formula.

How many substituents are on this alkane?

• 3

• 4

• 2

• 5

Answer explanation

There are four substituents branched from the parent hydrocarbon. 

How many bonds do carbon atoms form?

• 3

• 4

• 2

• 1

Answer explanation

Carbon atoms form 4 covalent bonds.

What are the two variables which are used to classify coal?

• boiling point and flammability

• hardness and carbon content

• flammability and combustibility

• color and hardness

Answer explanation

Coal is classified by its hardness and carbon content.