C10 - Reactions of alkenes

How do alkenes react with other elements?

The double bond separates to leave a single bond where new atoms are added, called addition reactions

WHat is the functional group for alkenes?

Carbon-Carbon double bond

What is hydregonation?

Addition of hydrogen as hydrogen reacts with the carbons and forms a saturated alkane

How is alcohol from alkenes are formed?

• Water is added to ethene producing ethanol

• The mixture is passed from reactors to a condenser

• Ethanol have a higher boiling point than ethene so condense while ethene is recycled back to the reactor

• The ethanol is purified using fractional distillation

How does bromine test for alkenes?

Bromine water is added to a saturated compound like alkane, so no reaction happen

When bromine water is added to alkenes, it makes a colourless compound so bromine is decolourized

WHat is the general formula for alcohols?

C_nH_2n+1OH

WHat is the functional group for alcohols?

-OH

WHat are properties of acohol?

• Flammable - Does combustion

• First four alcohols are soluble in water

What is produced when acohols are reacted with sodium?

Hydrogen + alkoxide

What happens when alcohol reacts with oxygen?

The alcohol is oxidised to produce carboxylic acid

Why are alcohols used as solvents?

Because they dissolve substances that water can and cannot dissolve

What are uses of alcohols?

• Drinks

• Solvents

• Fuels

What processes make ethanol?

• Fermentation: sugar → ethanol + CO2

• Reacting ethene with steam

WHat is teh optimum temperature for fermentation?

37C

WHat is the functional group of carboxylic acid?

-COOH

Ends with -anoic acid

What happens when carboxylic acid reacts with carbonates?

Produce salt, water and CO2

WHat is the reactions between ethanoic acid and sodium carbonate?

Ethanoic acid + sodium carbonate → Sodium ehtanoate + water + CO2

What happens when carboxylic acid dissolves in water?

They ionise and release H+ ions resulting in an acidic solution. However, they do not ionise completely so they form a weak acidic solution, meaning they have a higher pH

What is the functional group of esters?

-COO-

How are esters formed?

alcohol + carboxylic acid → Ester + water

What is the reaction between ethanoic aicd and ethanol?

Ethanoic acid + ethanol → ethyl ethanoate + water

What are polymers?

Lots of the same molecules joined together in one chain

What does polymerisation mean?

Lots of monomers joined togther to form a long molecule

What conditions does polymerisation need?

High pressures and a catalyst

What are plastics made up of?

Made up of polymers, usually carbon based and monomers are alkenes

What is addition polymerisation?

Unsaturated monomer molecules (alkenes) open their double bonds to form polymer chains

What are negative environmental impacts of polymers?

• Not biodegradeable

• Landfill sites quickly fill up

What do condensation polymerizations involve?

Monomers containing different functional groups

How are the polymers made from condensation?

The monomers react togteher and bonds form between them, forming polymer chains. For each new bond that forms, a smaller molecule is lost