Organic Chemistry Flashcards
What is the functional group alcohol?
-OH
What is the general formula for an alcohol
CnH2n+1OH
What are properties of alcohol?
They are flammable
Soluble in water - neutral pH
React with sodium to produce hydrogen
Can be oxidised to produce “carboxylic acid”
Uses of alcohol:
As alcoholic beverages As solvents In perfumes As fuels In hand sanitiser
What is ethanol made by?
Fermentation
What happens during fermentation?
An enzyme in yeast converts sugars into ethanol
What is the functional group of carboxylic acid?
-COOH
What does carboxylic acid form when reacted with carbonates?
A salt (-anoate), water and carbon dioxide
What happens when carboxylic acid dissolves in water?
They ionise and release H+ ions, making the solution acidic
Why is carboxylic acid a weak acid?
It doesn’t completely ionise in water
What is produced when carboxylic acid react with alcohol?
Esters
What is used to react carboxylic acid and alcohol?
An acid catalyst
What are polymers?
Long molecules that are formed when monomers join together
What is the functional group for esters?
-COO-
What is needed for polymerisation?
High pressure and catalyst
What type of monomers are needed for addition polymerisation?
Unsaturated monomers (alkenes) - have a double bond
How many products formed from addition polymerisation?
1 - the polymer
What molecules do condensation polymerisation occur between?
Molecules that contain 2 different functional groups
What happens when when a new bond forms during condensation polymerisation?
A small molecule is lost - usually water
Number of types of atoms for addition polymerisation:
1 monomer with a C=C bond
Number of types of atoms for condensation polymerisation:
2 monomer types each containing 2 of the same functional group (different from each other but each monomer only has 1 of the same)
1 monomer containing 2 different functional groups
Number of products from addition polymerisation:
1 product
Number of products from condensation polymerisation:
2 types of products - the polymer and a small molecule
Functional groups involved in condensation polymerisation:
2 reactive groups of each monomer
Functional groups involved in addition polymerisation:
Carbon-carbon double bond in monomer
How many functional groups do amino acids have?
2 different
What are the different functional groups an amino acid has
A basic amino group (NH2)
An acidic carboxyl group (COOH)
What polymers do amino acids form?
Polypeptides
How do amino acids form polypeptides?
Via condensation polymerisation
What are long chains of polypeptides known as?
Proteins
What gives the different properties and shapes of proteins?
The order of amino acids
What is DNA made up of?
2 polymer chains of monomers called nucleotides
What does each nucleotide contain?
A small molecule called a base
What do bases on different polymer chains do to keep the 2 strands of nucleotides together?
Pair up with each other and form cross links
What does the order of bases in DNA act as?
Code for an organism’s genes
What do sugars contain?
Carbon, oxygen, hydrogen
What can sugars form when reacted together through polymerisation?
Larger carbohydrate polymers e.g. starch and cellulose
metal + acid –>
salt + hydrogen
metal + alkali –>
salt + water
metal oxide + acid –>
salt + water
metal hydroxide + acid –>
salt + water
metal carbonate + acid –>
salt + water + carbon dioxide
metal + water –>
metal hydroxide + hydrogen
What are hydrocarbons made of?
Carbon and hydrogen atoms
What is the general formula of alkanes?
CnH2n+2
Are alkanes saturated compounds?
Yes
Why are alkanes saturates?
The carbon atoms only form (4) single bonds
What is meant by viscous?
Thick
What is meant by volatile?
Evaporates more easily - lower boiling points
Properties of hydrocarbons the shorter the chain:
Less viscous / more runny
More volatile
More flammable
What do the properties of hydrocarbons affect?
How they are used as fuels
When does complete combustion occur?
When there is plenty of oxygen
What does complete combustion release?
A lot of energy, water vapour and carbon dioxide
What from the hydrocarbon is oxidised during combustion?
Both carbon and hydrogen
Why are hydrocarbons used as fuels?
They release a lot of energy when they combust completely
When does incomplete combustion take place?
When there is a poor supply of oxygen
Why would people prefer to use an alkane instead of an alkene during combustion?
Alkenes are more likely to undergo incomplete combustion while alkanes release more energy during combustion
Why use octane instead of octene in a car engine?
4 marks
Octene tends to undergo incomplete combustion so produces smokier flames
It also prodces more CO, which is poisonous
Octane releases more energy during combustion than octene
Octane is a more efficient fuel
How does crude oil form?
From remains of plants and animals, mainly plankton, buried under mud under high pressure and temperatures
What is crude oil?
A mixture of lots of different hydrocarbons
How are different compounds separated in crude oil?
Using fractional distillation
What has to be done to the crude oil before it can enter the fractionating column?
It has to be vapourised
What is the temperature gradient like in the fractionating column?
It becomes cooler as you go up the fractionating column
What happens to the vapour as it rises up the fractionating column?
It cools and condenses at their boiling points, at different levels
Why does the vapour condense at different boiling points in the fractionating column?
Because different hydrocarbons have different boiling points
Where do longer hydrocarbons condense and why?
They condense quickly, near the bottom because they have high boiling points
Where do shorter hydrocarbons condense and why?
They condense near the top because they have low boiling points
What does each fraction contain?
A mixture of hydrocarbons with a similar number of carbon atoms and therefore similar boiling points
What happens during fractional distillation?
The crude oil is vapourised and entered into the fractionating column. The vapour rises up the column before cooling and condensing at their boiling points, at different levels, because different hydrocarbons have different boiling points. This happens because the column has a temperature gradient, become cooler as you go up the fractionating column. Long hydrocarbons condense quickly, near the bottom because they have high boiling points while short hydrocarbons condense near the top because they have low boiling points. The crude oil is separated into different factions, mixtures of hydrocarbons with a similar number of carbon atoms and therefore similar boiling points
What can crude oil be used foe?
Fuel - for transport
To make compounds such as polymers, solvents, lubricants
What type of reaction is cracking?
Thermal decomposition
Why are short-chain hydrocarbons in high demand?
Because they are flammable and therefore make good fuels
How are long alkane molecules made useful?
They are broken down into smaller molecules through cracking
What does cracking produce?
An alkene and an alkane
How are alkenes useful?
They can be used to make polymers
What are the 2 types of cracking?
Cracking with a catalyst
Cracking with steam
What happens when cracking with a catalyst?
The large hydrocarbons are vapourised
The vapour is passed over a hot catalyst
The long-chain molecules split up on the surface of the catalyst - catalytic cracking
What happens when cracking with steam?
The large hydrocarbons are vapourised
The vapour is mixed with steam
It is then heated to a very high temperature
What is the general formula of an alkene?
CnH2n
Why are alkenes saturated?
They have a double C=C bond
What do alkenes have?
They have a double bond between 2 of the carbon atoms
Why are alkenes more reactive than alkanes?
Because the double C=C bond can open up to make a single bond, allowing the 2 carbon atoms to bond with other atoms
In a large amount of oxygen, alkenes combust _________ to produce ____ + _____ ______
Completely
Water
Carbon dioxide
What else is produced when alkenes undergo incomplete combustion?
Carbon or carbon monoxide
What happens during an addition reaction?
The carbon-carbon double bond opens up to leave a single bond and a new atom is added to each carbon
What is hydrogenation?
Addition of hydrogen
What does the hydrogenation of alkene produce?
A saturated alkane
During hydrogenation, the _____ is reacted with ________ in the presence of a _______
Alkene
Hydrogen
Catalyst
What is formed when an alkene is reacted with steam?
Alcohol
Ethanol can be made by mixing _____ with ____ and then passing it over a _________
Ethene
Steam
Catalyst
Do alkenes react with halogens?
Yes
Is the molecule formed when halogens and alkenes react saturated or unsaturated?
Saturated
What is formed when bromine and ethene reacts?
Dibromoethane
How can you test for alkenes?
Add bromine
What happens when bromine water is added to an alkane?
No reaction takes place - it remains orange
What happens when bromine water is added to an alkene?
The bromine will add across the double bond making a colourless compound
What colour is dibromoethane?
Colourless
