Organic Chemistry Paper 2 Flashcards
What is a hydrocarbon
Compounds that only contain hydrogen and carbon
What is crude oil
The remains of dead organisms that lived millions of years ago
What is crude oil an important source of
Fuel and feedstock
What is crude oil an important source of
Fuel and feedstock
What is the general formula for alkanes
CnH2n+2
What are the first 4 alkanes you need to know
Methane
Ethane
Propane
Butane
Are alkanes saturated or unsaturated hydrocarbons
Saturated as it’s a single bond
Describe the process of fractional distillation
First heat the crude oil. heated crude oil enters a tall fractionating column which is hot at the bottom and gets cooler towards the top. vapours from the oil rise through the column vapours condense when they become cool enough. liquids are led out of the column at different heights
Why do small hydrocarbon molecules have low boiling points
They have weak intermolecular forces that don’t require a lot of energy to overcome
What is viscosity
A measure of how difficult it is for the substance to flow- higher viscosity means it’s more thick
What properties do smaller hydrocarbons have
Boiling points below room temperature
Very flammable
Low viscosity
What properties do larger hydrocarbons have
High boiling point (above room temperature)
Difficult to ignite
High viscosity
When does complete combustion occur
When there is a good supply of air(oxygen)
Is complete combustion exothermic or endothermic
Exothermic
What is the word formula for complete combustion
Hydrocarbon +oxygen —-> carbon dioxide +water
What is the word equation of incomplete combustion
Hydrocarbon + oxygen——-> carbon monoxide + water
What is cracking
Cracking
is a reaction in which larger saturated
hydrocarbon molecules are broken down into smaller, more useful hydrocarbon molecules, some of which are unsaturated
Hexane is cracked to form butane and what (C6H14 → C4H10 +??)
Ethene
What are the two types of cracking
Catalyst and steam
Why is cracking important
Produces alkenes which are useful for feedstock for the petrochemical industry
Are alkene saturated or unsaturated hydrogen carbons and why
Unsaturated as it has a double bond
What is the test for alkenes and the result
Bromine water
Orange—> colourless
What is the general formula for alkenes
CnH2n
What is the product of an alkene + water
Alcohol
What is the general formula for alcohols
CnH2n+1OH
Is fermentation an aerobic or anaerobic process
Anaerobic as it does not require oxygen
What are the required conditions for fermentation
Warm temperatures 25 -35 degrees
sugars dissolved in water, and mixed with yeast 40⁰c
an air lock to allow carbon dioxide out, while stopping air getting in
What is the word equation for fermentation
glucose → ethanol + carbon dioxide
What are the first 4 alcohols
Methanol
Ethanol
Propanol
Butanol
When alcohols are oxidised what do they produces
A carboxylic acid
What is the functional group of carboxylic acids
COOH
What is produced when a carboxylic acid reacts with an alcohol
Ester and water
What is a polymer
A large molecule formed from many identical smaller molecules know as monomers
Alcohol + water?
Neutral solution
carboxylic acid + metal carbonate?
When carboxylic acids react with metal carbonates, they form a salt, water and carbon dioxide
Carboxylic acid + water? Why?
Weak acid as partially ionises in water
ethanoic acid + ethanol?
ethanoic acid reacts with ethanol it forms the ester ethyl ethanoate + water
What is polymerisation? Types?
Monomer molecules react together to form polymers
addition polymerisation condensation polymerisation
Additional polymerisation?
Alkenes
Condensation polymerisation?
With 2 functional groups
Water is produced
OH + COOH forms a polyester
