alkanes and alkenes

What are alkanes?

Alkanes are saturated hydrocarbons with only single bonds between carbon atoms. Their general formula is CₙH₂ₙ₊₂.

What is the general formula for alkanes?

The general formula for alkanes is CₙH₂ₙ₊₂, where "n" represents the number of carbon atoms.

Are alkanes saturated or unsaturated hydrocarbons?

Alkanes are saturated hydrocarbons, meaning they contain only single bonds between carbon atoms.

4. List the first four alkanes and their molecular formulas?

• Methane: CH₄

• Ethane: C₂H₆

• Propane: C₃H₈

• Butane: C₄H₁₀

What are alkenes?

Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond (C=C). Their general formula is CₙH₂ₙ. 6. What is the general formula for alkenes

Are alkenes saturated or unsaturated hydrocarbons?

Alkenes are unsaturated hydrocarbons because they contain at least one carbon-carbon double bond.

List the first four alkenes and their molecular formulas?

• Ethene: C₂H₄

• Propene: C₃H₆

• Butene: C₄H₈

• Pentene: C₅H₁₀

What is the functional group present in alkenes?

The functional group in alkenes is the carbon-carbon double bond (C=C).

How can you test for the presence of alkenes?

bromine water will change it from orange/brown to colourless if alkenes are present

What type of reactions do alkanes undergo?

primarily undergo combustion reactions and substitution reactions due to the stability of their single bonds.

What type of reactions do alkenes undergo?

Alkenes undergo addition reactions, such as with hydrogen (hydrogenation), halogens (e.g., bromine), and steam (hydration).

What happens during the hydrogenation of an alkene?

hydrogen is added to an alkene, breaking the double bond and forming a saturated alkane.

What is the difference between complete and incomplete combustion of alkanes?

• In complete combustion, alkanes burn in excess oxygen, producing carbon dioxide and water.

• In incomplete combustion, where oxygen is limited, carbon monoxide and water (and sometimes carbon in the form of soot) are produced.

Why are alkenes considered more reactive than alkanes?

Alkenes are more reactive than alkanes because of the presence of the carbon-carbon double bond, which is more reactive than single bonds in alkanes.

What is the process called when small alkanes and alkenes are formed from large hydrocarbon molecules?

The process is called cracking, where large hydrocarbons are broken down into smaller, more useful alkanes and alkenes.

What are the two main methods of cracking hydrocarbons?

The two main methods of cracking are:

• Catalytic cracking: uses a catalyst and moderate temperature.

• Steam cracking: uses high temperature and steam.

What is a polymer?

A polymer is a long-chain molecule made up of repeating units called monomers. Alkenes can act as monomers in polymerization reactions.

What happens during the polymerization of alkenes?

alkene molecules (monomers) react to form long-chain polymers by opening their double bonds.

What is the environmental concern related to the combustion of alkanes?

The combustion of alkanes, especially in incomplete combustion, can release pollutants such as carbon monoxide, which is toxic, and contributes to air pollution and climate change through the release of carbon dioxide.

what is the general formula for alkanes?

CnH2n+2

what is the general formula for alkenes?

CnH2n