Chemistry: Alkanes and Alkenes

What is the general formula for alkanes?

• CnHn

• CnH2n-2

• CnH2n

• CnH2n+2

Answer explanation

The general formula for alkanes is CnH2n+2. This formula represents that for every carbon atom, there are two hydrogen atoms plus two more hydrogen atoms.

How many total atoms are present in heptane?

• 23

• 24

• 25

• 26

Answer explanation

Heptane is a hydrocarbon with the molecular formula C7H16. To find the total number of atoms present in heptane, we add together the number of carbon atoms and the number of hydrogen atoms.

Number of carbon atoms (C) = 7 Number of hydrogen atoms (H) = 16

Total atoms in heptane = Number of carbon atoms + Number of hydrogen atoms Total atoms in heptane = 7 (C) + 16 (H) Total atoms in heptane = 23

What is the difference between alkanes and alkenes?

• The difference is that alkanes have only single bonds between carbon atoms, while alkenes have at least one double bond between carbon atoms.

• Alkanes have double bonds and alkenes have single bonds

• Alkanes have more carbon atoms than alkenes

• Alkanes are solid at room temperature while alkenes are liquid

Answer explanation

Alkanes have single bonds, while alkenes have at least one double bond between carbon atoms.

What is the double bond present in alkenes made up of?

• Two ionic bonds between the carbon atoms

• Two covalent bonds between the carbon atoms

• A metallic bond between the carbon atoms

• A single covalent bond between the carbon atoms

Answer explanation

The double bond in alkenes is made up of two covalent bonds between the carbon atoms.

What is the name of the alkene with two carbon atoms?

• Ethene

• Butene

• Propene

• Methene

Answer explanation

The correct name of the alkene with two carbon atoms is Ethene. Ethene is a two-carbon alkene and is the correct choice.

Isomer of 4-methyl hexane is ... .

• 4-ethyl hexane

• 2-methyl hexane

• 3-methyl hexane

• 1-methyl hexane

What is the process by which alkanes are converted to alkenes?

• Oxidation or reduction

• Hydrolysis or polymerization

• Substitution or addition

• Dehydrogenation or catalytic cracking

Answer explanation

Alkanes are converted to alkenes through dehydrogenation or catalytic cracking, a process that removes hydrogen atoms and breaks carbon-carbon bonds.

A family of organic compound with similar chemical properties and same general formula as formula as found on periodic table, called ... .

• hydrogen series

• isomer series

• homologous series

• heterogenous series

What is the difference between saturated and unsaturated hydrocarbons?

• Saturated hydrocarbons have at least one double or triple bond between carbon atoms, while unsaturated hydrocarbons have only single bonds.

• Saturated hydrocarbons have no bonds between carbon atoms, while unsaturated hydrocarbons have single or double bonds.

• Saturated hydrocarbons have single bonds between carbon atoms, while unsaturated hydrocarbons have at least one double or triple bond between carbon atoms.

• Saturated hydrocarbons have double bonds between carbon atoms, while unsaturated hydrocarbons have single bonds.

Answer explanation

Saturated hydrocarbons have single bonds between carbon atoms, while unsaturated hydrocarbons have double or triple bonds.

What is the name of this hydrocarbon?

• 1-butane

• 1-butene

• 2-butana

• 2-butene