Hydrocarbons: alkanes, alkenes, alkynes
Only carbon and hydrogen.
Carbon and hydrogen only
Methane, ethane, ethene and ethyne are all made of just two elements: carbon and hydrogen.
What do you think such compounds are called?
What this lesson covers
The idea
Compounds of only carbon and hydrogen are hydrocarbons; saturated hydrocarbons are alkanes, those with one or more double bonds are alkenes, and those with one or more triple bonds are alkynes.
Carbon and hydrogen only
Methane, ethane, ethene and ethyne are all made of just two elements: carbon and hydrogen.
What do you think such compounds are called?
- Hydrocarbons
- Carbonates
- Alcohols
Match the family
Tap a description on the left, then its name on the right.
Three families
Alkanes have only single bonds between carbon atoms. Alkenes have one or more double bonds. Alkynes have one or more triple bonds. All three contain only carbon and hydrogen.
Compounds of only carbon and hydrogen are hydrocarbons. Saturated hydrocarbons are alkanes, those with one or more double bonds are alkenes, and those with one or more triple bonds are alkynes.
- Family | Bonds between carbon atoms | Example
- Alkane | only single bonds | propane, C₃H₈
- Alkene | one or more double bonds | ethene, C₂H₄
- Alkyne | one or more triple bonds | ethyne, C₂H₂
Notes
Compounds of only carbon and hydrogen are hydrocarbons: alkanes are saturated, alkenes have one or more double bonds and alkynes have one or more triple bonds.
Check yourself
Which of these is a hydrocarbon?
Ethene, C₂H₄, has a double bond between its carbon atoms. What is it?
Ethyne, C₂H₂, has a triple bond between its carbon atoms. What is it?
Propane, C₃H₈, has only single bonds between its carbon atoms. What is it?
- Ethanol, C₂H₅OH. Ethanol also contains oxygen, so it is not made of only carbon and hydrogen.
- Chloroform, CHCl₃. Chloroform also contains chlorine, so it is not made of only carbon and hydrogen.
- Propane, C₃H₈ — correct. Yes!
- An alkene — correct. Yes!
- An alkane. Alkanes are saturated hydrocarbons, with only single bonds between carbon atoms.
- An alkyne. Alkynes have one or more triple bonds.
- An alkene. Alkenes have one or more double bonds.
- An alkyne — correct. Yes!
- An alkane. Alkanes are saturated hydrocarbons, with only single bonds between carbon atoms.
- An alkene. Alkenes have one or more double bonds, and propane has none.
- An alkyne. Alkynes have one or more triple bonds, and propane has none.
- An alkane — correct. Yes!