Hydrocarbons are compounds made up of hydrogen and carbon atoms...
Chemistry344 views·Updated 4 Sept 2026·2 pagesUnderstanding Alkanes and Alkenes
paige gibbs@paigegibbs_vuvr
1
of 2
Alkanes - The Saturated Hydrocarbons
Alkanes are like the steady, reliable friends of the hydrocarbon world. Each carbon atom links to four other atoms using single bonds, making them saturated hydrocarbons - they've got the maximum number of hydrogen atoms possible.
These molecules follow the general formula CₙH₂ₙ₊₂. Starting simple: methane (CH₄) has one carbon, ethane (C₂H₆) has two carbons, propane (C₃H₈) has three, and butane (C₄H₁₀) has four. Notice how each carbon is surrounded by hydrogen atoms in a neat, predictable pattern.
Alkanes are fairly unreactive in normal conditions, but they burn brilliantly - that's why we use them as fuels. Shorter chains like methane release energy more quickly when burning, making them perfect for cooking gas.
💡 Remember: The single lines between atoms represent single covalent bonds - one pair of electrons being shared between two atoms.
All alkanes belong to a homologous series, meaning they share the same functional group and follow the same general formula, just with different chain lengths.
2
of 2
Alkenes - The Unsaturated Hydrocarbons
Alkenes are the rebels compared to alkanes - they're unsaturated hydrocarbons with a crucial difference. Instead of all single bonds, they contain at least one C=C double bond, which makes them much more reactive and interesting.
The general formula for alkenes is CₙH₂ₙ - notice there are fewer hydrogen atoms than in alkanes. This happens because the double bond "uses up" some bonding opportunities that hydrogen would normally fill.
Starting with ethene (C₂H₄), then propene (C₃H₆), and butene (C₄H₈), you can see how the pattern develops. The double bond is the star of the show - it's what makes alkenes so useful for making plastics and other materials.
💡 Key insight: The C=C double bond makes alkenes reactive because it can break open to form new bonds with other molecules.
Like alkanes, alkenes form a homologous series with similar chemical properties but gradually changing physical properties like boiling points as the chains get longer.
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Chemistry344 views·Updated 4 Sept 2026·2 pagesUnderstanding Alkanes and Alkenes
paige gibbs@paigegibbs_vuvr
Hydrocarbons are compounds made up of hydrogen and carbon atoms only, and they're everywhere in our daily lives - from the petrol in cars to the gas that heats our homes. Understanding alkanes and alkenes is crucial for your chemistry...
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Alkanes - The Saturated Hydrocarbons
Alkanes are like the steady, reliable friends of the hydrocarbon world. Each carbon atom links to four other atoms using single bonds, making them saturated hydrocarbons - they've got the maximum number of hydrogen atoms possible.
These molecules follow the general formula CₙH₂ₙ₊₂. Starting simple: methane (CH₄) has one carbon, ethane (C₂H₆) has two carbons, propane (C₃H₈) has three, and butane (C₄H₁₀) has four. Notice how each carbon is surrounded by hydrogen atoms in a neat, predictable pattern.
Alkanes are fairly unreactive in normal conditions, but they burn brilliantly - that's why we use them as fuels. Shorter chains like methane release energy more quickly when burning, making them perfect for cooking gas.
💡 Remember: The single lines between atoms represent single covalent bonds - one pair of electrons being shared between two atoms.
All alkanes belong to a homologous series, meaning they share the same functional group and follow the same general formula, just with different chain lengths.
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Alkenes - The Unsaturated Hydrocarbons
Alkenes are the rebels compared to alkanes - they're unsaturated hydrocarbons with a crucial difference. Instead of all single bonds, they contain at least one C=C double bond, which makes them much more reactive and interesting.
The general formula for alkenes is CₙH₂ₙ - notice there are fewer hydrogen atoms than in alkanes. This happens because the double bond "uses up" some bonding opportunities that hydrogen would normally fill.
Starting with ethene (C₂H₄), then propene (C₃H₆), and butene (C₄H₈), you can see how the pattern develops. The double bond is the star of the show - it's what makes alkenes so useful for making plastics and other materials.
💡 Key insight: The C=C double bond makes alkenes reactive because it can break open to form new bonds with other molecules.
Like alkanes, alkenes form a homologous series with similar chemical properties but gradually changing physical properties like boiling points as the chains get longer.
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