C10: Organic reactions Flashcards
Describe the combustion of alkenes
Complete - Same as alkanes - produce carbon dioxide and water
Incomplete - more likely to take place with alkenes, produces unburnt carbon and therefore they are more likely to undergo incomplete combustion
What does the burning of alkenes look like?
Smoky flame
What is hydrogenation and what conditions does it require?
An alkene reacting with hydrogen,
Requires high temp and a nickel catalyst
What happens during the hydrogenation of an alkene?
An alkane is produced
Why do alkenes react similarly?
They are in the same homologous series - they have the same functional group
What is hydration and what conditions does it require?
The reaction between an alkene and water
- requires high temp (300C) and pressure (70atm) and phosphoric acid catalyst, water MUST be in steam
it is reversible
What is produced after the hydration of an alkene?
An alcohol
What happens when an alkene reacts with a halogen?
It forms a colourless solution and a dibromoalkane
What is the general formula for alcohols?
CnH2n+1OH
What are alcohols used in?
Fuels
Solvents
Drinks
What is the functional group of alcohols?
-OH
What are 2 ways to make ethanol?
Fermentation of yeast (no oxygen, 30C)
Hydration of ethene
Evaluate the 2 ways to make ethanol
Fermentation - renewable (sugar from plants), low temp (little energy \, aqueous solution of ethanol, requires purification
Hydration - very high yield // high temp (lots of energy = lots of money), ethene required is non-renewable
What is the solubility of alcohols in water like?
Soluble, form neutral solutions
As the number of carbon atoms increases, solubility decreases
What happens when alcohols react with sodium?
Produce sodium salt and hydrogen
Bubbles being produced
What happens when alcohols react with oxidising agents?
Produce a carboxylic acid and water
What happens when alcohols combust completely?
Produce carbon dioxide and water
What is the general formula of carboxylic acids?
CnH2n+1COOH
What is the functional group of carboxylic acids?
-COOH
What happens when dissolving carboxylic acids in water?
Form weak acids (partially dissociate) to form a negative ion (e.g. ethanoate) and a positive hydrogen ion (H+) (all aq). Have a HIGHER pH
What is formed when carboxylic acids react with metal carbonates?
Form salt, carbon dioxide and water
What is produced when carboxylic acids react with alcohols?
Ester + water
What are some uses of esters?
Perfumes, fruity smells and solvents
What is the one ester you have to remember?
Ethyl ethanoate
