Chapter 18: Organic chemistry Alkanes and Alkenes

What is the general formula of alkanes?

The general formula of alkanes is CₙH₂ₙ₊₂

What is the general formula of alkenes?

The general formula of alkenes is CₙH₂ₙ

What is the main difference between alkanes and alkenes?

Alkanes are saturated hydrocarbons with only single bonds, while alkenes are unsaturated hydrocarbons with at least one double bond

What is the test for unsaturation in hydrocarbons?

The test for unsaturation is the addition of bromine water. If the bromine water is decolorized, the hydrocarbon is unsaturated (contains a double bond)

What type of reaction do alkenes undergo?

Alkenes undergo addition reactions, where atoms add across the carbon-carbon double bond

Describe the difference in the chemical reactivity of alkanes and alkenes.

Alkanes are relatively unreactive because they contain only single bonds (C-C), while alkenes are more reactive because they contain a carbon-carbon double bond (C=C), which can easily break and form new bonds in addition reactions

How can you distinguish between an alkane and an alkene in the laboratory?

Add bromine water to both compounds. If the bromine water is decolorized, the compound is an alkene (unsaturated). If there is no color change, it is an alkane (saturated)

Write a balanced equation for the reaction between ethene (C₂H₄) and bromine (Br₂).

C₂H₄ + Br₂ → C₂H₄Br₂