chemistry topic 7 Flashcards
what is crude oil
Crude oil is a finite resource, mixture of hydrocarbons (made up of carbon and hydrogen only)
what is the order of the fractions in a fractional distillation column from lowest boiling point to highest boiling point
- butane and propane
2 . petrol - kerosene
- Diesel
- fuel oil
describe Fractional distillation
Fractionating column is cool at the top and hot
at the bottom
- Heat crude oil (vaporise it)
- Hydrocarbons evaporate and rise
- When a fraction of the hydrocarbons cool to
their boiling point they condense - Liquids are then extracted
what effect does Decreasing molecular size have
- boiling point decrease
- viscosity decrease
- flammability increases.
Fractions from crude oil can be processed to produce feedstock for the petrochemical
industry. what are useful materials produced from this feedstock?
- Solvents – nail varnish remover
- Lubricants – oil for car engines
- Polymers – polythene and polyvinyl chloride PVC
*Detergents – washing up liquid
what does the combustion of hydrocarbons release
energy
describe complete combustion
Hydrocarbons are oxidised and produce carbon dioxide and water.
what is the prefix is something has one carbon
meth-
what is the prefix if something has two carbon
eth-
what is the prefix if something has three carbons
prop-
what is the prefix if something has four carbons
but-
what is the suffix and functional group of Alkanes
-ane
-C-C-
what is the suffix and functional group of Alkenes
-ene
-C=C-
what is the suffix and functional group of Alcohols
-ol
-COH
what is the suffix and functional group of Carboxylic acids
-oic acid
-COOH
what is the suffix and functional group of esters
Alkyl- -oate
-COOC-
what is the suffix and functional group of Amine
-ine
-NH2
what is the general formula for Alkanes
CnH2n+2.
They are ALL SATURATED – no double bonds
what is the general formula for Alkenes
CnH2n
UNSATURATED hydrocarbons with a double carbon-carbon
bond.
why is there no chemical called methene,
There is no chemical called methene, as the double bond must be between two carbons. Any hydrocarbon starting with meth- can only have one carbon.
how do alkenes react in combustion reactions
Alkenes react with oxygen in combustion reactions in the same wayas other
hydrocarbons, but they tend to burn in air with smoky flames because of
incomplete combustion.
what is cracking
Hydrocarbons can be broken down (cracked) to produce
smaller more useful molecules.
describe Catalytic cracking
the hydrocarbon is heated to a high temperature and a
Zeolite catalyst is used
describe Steam cracking
the hydrocarbon is heated and mixed with steam
how to test for alkenes
react with orange-brown bromine water to turn it colourless.
what can alkenes be used for
Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.
What are alkanes?
alkanes are hydrocarbons or are compounds of hydrogen and carbon only
what happens when When ethanol reacts with sodium
bubbles of hydrogen gas are given off and colourless sodium ethoxide solution is left
what happens when alcohols react with an oxidising reagent
Alcohols can react with an oxidising reagent to make the carboxylic acid
e.g. ethanol will oxidise to make ethanoic acid.
what are the two process for producing ethanol
- Fermentation – sugar + water + yeast.
25 0C – 45 0C. Anaerobic
Glucose → Ethanol + Carbon Dioxide
- Hydration – Ethene + steam.
300 0C. Catalyst
ethene + Steam → Ethanol
what are the important reactions for Carboxylic acids
Carboxylic acid + metal carbonate → salt + carbondioxide + water
propanoic acid + Sodium
carbonate→ sodium propanoate +carbon dioxide +water
Carboxylic acid + alcohol → ester + water
Ethanoic acid + ethanol → ethyl ethanoate +water
whats the diffrence between strong and week acids
week acids are partially ionised in water strong acids are fully ionised in water
how do Alkenes make polymers
addition polymerisation:
poly(ethene) and poly(propene)
how can esters be made from carboxylic acid
alcohol + carboxylic acid → ester + water
what does Condensation polymerisation involve
involves Monomers joining and losing water
give examples of natural polymers
DNA – nucleotides
Starch – glucose
Proteins – amino acids
what functional groups do amino acids have
Amino acids have amine – NH2 and carboxylic acid - COOH
how can proteins be produced
Different amino acids can be
combined in the same chain to
produce proteins.
DNA molecules are how many polymer chains
two
Each nucleotide in DNA contains what
Each nucleotide contains a base, a phosphate and a sugar.
