C7 Flashcards
What is crude oil?
A finite resource found in rocks.
How was crude oil made?
Over millions of years and lots of pressure; it is buried plankton which is drilled up now.
What is crude oil mainly made up of?
Hydrocarbons: mainly alkanes.
What is a hydrocarbon?
A compound made of hydrogen and carbon atoms
What is the formula for alkanes?
CnH2n+2
What are the first 4 alkanes?
Methane. Ethane. Propane. Butane.
Where might the fractions from fractional distillation be used?
To produce fuels and feedstock for the petrochemical industry.
What are some examples of fuels which are made from crude oil?
Petrol; diesel; kerosene; heavy fuel oil and liquified petroleum gases.
What are some examples of things that are produced by the petrochemical industry?
Solvents; lubricants; polymers and detergents.
How does fractional distillation work? (4)
- The crude oil is heated and it evaporates. 2. It travels up the fractionating column - the bottom is the hottest and the top is the coolest. 3. The different fractions condense at different points due to their different boiling points. 4. Each faction is now separated :) and ready for use.
How does boiling point; viscosity; flammability and size change for hydrocarbons?
The smaller the hydrocarbon: less viscous (more runny); more flammable and a lower boiling point (more volatile). The bigger: more viscous; less flammable and a higher boiling point.
What is the equation for the complete combustion of hydrocarbons?
Hydrogen + oxygen –> water + carbon dioxide ( + energy)
What does cracking do?
Breaks long chain hydrocarbons into shorter and more useful hydrocarbons.
What are the 2 types of cracking?
Steam - needs a high temperature and catalytic - needs a high temperature and a catalyst.
What are the products of cracking?
Alkanes and some alkenes.
What is the test for alkenes?
Add bromine water —> colourless
What is distinctive about alkenes?
Double bond with carbon
What’s the equation for alkenes and what does that make them?
Cn H2n - unsaturated.
What are the first 4 alkenes?
Ethene, propene, butene, pentene
What are alkenes used for?
To produce polymers and as starting materials to produce other chemicals
What is the functional group of alkenes?
C=C
In a large amount of oxygen, do alkenes combust fully?
Yes
But what happens when there’s a lack of oxygen for alkenes?
They undergo incomplete combustion which produces carbon dioxide and water (as usual) and carbon and carbon monoxide. It burns in the air with a smoky yellow flame and produces less energy.
What happens when an alkene reacts with hydrogen?
Addition reaction - opens up the carbon carbon double bond and forms a saturated alkane. Must be in the presence of a catalyst.
What happens when you add water to an alkene?
Steam, water is added across the carbon carbon double bond and forms an alcohol
When happens if you react an alkene with a halogen?
The halogen is diatomic and just joins onto the carbon single bond.
What is the functional group of an alcohol?
OH
What are the first four alcohols?
Methanol; ethanol; propanol; butanol
What are the symbols for an alcohol e.g. ethanol?
CH3CH2OH
What is a key property of alcohols?
They’re flammable
What happens when alcohols react with sodium?
Hydrogen is produced. E.g. ethanol + sodium -> sodium ethoxide + hydrogen
What happens when alcohols burn in the air?
Complete combustion and carbon dioxide and water is produced.
What happens when alcohols are added to water?
They dissolve to give neutral solutions
What happens when alcohols react with an oxidising agent?
They are oxidised and produce a carboxylic acid.
What are the main uses of alcohols?
Fuels. Solvents. Alcoholic drinks
How is ethanol made using fermentation?
There’s an enzyme in the yeast which converts sugars into ethanol. Carbon dioxide is also produced.
What are the conditions for fermentation?
37 degrees in a slightly acidic solution and under anaerobic conditions. Enzyme would be denatured if under different conditions.
What is the functional group for carboxylic acids?
COOH
What are the first four carboxylic acids?
Methanoic acid. Ethanoic acid. Propanoic acid. Butanoic acid
What is the formula of a carboxylic acid?
CH3CO(double bond)OH
What happens when a carboxylic acid reacts with carbonates?
Produces a salt; water and carbon dioxide.
What happens when a carboxylic acid dissolves in water?
When they dissolve; they ionise and release H+ ions resulting in an acidic solution. They don’t ionise completely so they form weak aidic solutions.
What happens when a carboxylic acid reacts with alcohols?
Esters are formed. An acid catalyst is usually used.
What is the all important ester and what are its properties?
Ethyl ethanoate - smells nice and insoluble in water.
How can alkenes be used to make polymers such as polyethene and polypropene?
Addition polymerisation
What happens in addition polymerisation?
Many small molecules (monomers) join together to form very large molecules (polymers)
Compare ethene to polyethene
C=C (and 4 H around). Polyethene C-C with brackets and lines and an n
What is condensation polymerisation?
Where monomers with two functional groups join together, usually losing small molecules such as water.
What do amino acids have?
Two different functional groups in a molecule
How can amino acids produce polypeptides?
They react by condensation polymerisation
What is the polymer for amino acids?
Protein
What are the monomers for DNA and what’s the structure like?
Nucleotides in a double helix
What are the polymers that are essential for life?
DNA; starch; proteins and cellulose
What are the monomers for starch?
Glucose
What are the monomers for cellulose?
Glucose
