C10 Flashcards
What is a homologous series ?
It is a family of organic compounds with the same functional group
Whats the general formula for alkenes ?
CnH2n
Why are alkenes not used for fuels ?
Because there is complete combustion and they also release less energy per mole in combustion than alkanes
What makes alkenes more reactive than alkanes ?
Its the c-c double bond that makes alkenes more reactive than alkanes. Molecules that react with alkenes add to the alkene across their double bonds
What happens when alkenes react with bromine and whats the general formula for the reaction ?
The orange colour in bromine water comes from Br2 molecules, which are converted into a colourless product called dibromoethane when they react with a alkene
Ethene (alkene) + bromine —–> dibromoethane
What happens when a alkene react with hydrogen ?
Alkenes are unsaturated hydrocarbons therefore they dont contain the maximum amount of hydrogen atoms in the hydrocarbon molecule. But with the addition of H2 across the double bond of the alkene, will form a saturated alkane. This reaction takes place at 60 degrees celcius in the presence of a nickel catalyst.
What happens when a alkene reacts with water (steam) ?
Ethene is the main by-product in cracking and it can react with steam to make ethanol.
The reaction requires energy to heat the gases and to generate a high pressure
The reaction is also reversible so the ethanol can break back into ethene and steam
What is an alcohol ?
It is the same thing as an alkane but imagine taking one of the hydrogens and replacing it with OH
The functional group for alcohols is OH
What is a carboxylic acid ?
It has the functional group COOH and there is a double bond between one of the C and O atoms and then a single bond bewteen the other C and O atoms
What is an ester ?
If you replace the H atom in the COOH group by a hydrocarbon, such as CH3 or C2H5, you would get an ester.
An esters functional group is COO
What are alcohols used as?
Used as solvents and fuels
What is the main alcohol in alcoholic drinks ?
Ethanol
How is ethanol made by fermentation ?
Glucose —-> ethanol + carbon dioxide
How can ethanol be made in industry’s ?
By reacting ethene (obtained by cracking heavy fractions from crude oil ) and steam in the presence of a catalyst. But this method uses up crude oil
What is the general formula for alcohols reacting with oxygen ?
Alcohol + oxygen —-> carbon dioxide + water