GCSE Chemistry- C7 Organic Chemistry

What is crude oil?

a finite fossil fuel that contains a mixture of long and short chains of hydrocarbons

Where is crude oil found?

oil found in rocks and made from ancient biomass

How is crude oil formed?

fossils of dead plants and animals at the bottom of the sea from millions of years ago which had layers of rock built on top over time, causing hot and high pressure conditions, forming crude oil.

What are alkanes?

an example of a hydrocarbon

What is a hydrocarbon?

a compound made up of hydrogen and carbon

What are the first 4 alkanes?

Methane, ethane, propane, butane

What is the chemical formula and structure for methane?

CH4

What is the chemical formula and structure for ethane?

C2H6

What is the chemical formula and structure for propane?

C3H8

What is the chemical formula and structure for butane?

C4H10

What is the general formula for alkanes?

CnH2n+2

What is the molecular formula?

total number of each type of atom

What is the emperical formula?

simplest whole number ratio of elements

What is the structural formula?

visual structure of how atoms are bonded

What are problems with crude oil?

viscous, not flammable, impure

What does a longer hydrocarbon chain mean?

stronger intermolecular forces, therefore more energy needed to break bonds (higher melting+boiling points)

What is distillation?

a process to separate a mixture by heating to each of its boiling points

What is fractional distillation?

separation into fractions of similar sized hydrocarbons (number of carbon atoms) using their different boiling points

What is the order of a fractionating column from hot to cold?

heated/vaporised crude oil, bitumen, diesel, kerosene, naphtha, petrol, gas

What is the structure of a fractionating column?

the heated/vaporised crude oil enters from the bottom of the column, as the hot air rises, it gets cooler, condensing into different compounds based on the hydrocarbon chain length, as the longest length requires more energy to break bonds.

What does the size of the condensed molecule mean?

largest molecule= high boiling point, smallest molecules= low boiling point

What is a fraction?

A mixture of hydrocarbons with similar boiling points

What are properties of short chain hydrocarbons?

easy to ignite, less viscous, more useful as fuels

What are properties of long chain hydrocarbons?

harder to ignite, more viscous, more useful as fuels

What is cracking?

process of braking down the larger alkanes into smaller, more useful ones.

What is cracking used in?

thermal decomposition reactions- breaking down molecules by heating them

What is the cracking reaction?

alkane -> shorter alkane + alkene

What is an alkene?

another type of hydrocarbon with double bonds between carbon atoms

What is the chemical formula for alkenes?

CnH2n

What are the types of cracking?

Steam cracking and catalytic cracking

What is steam cracking?

cracking requiring high temperature (800C) mixed with steam

What is catalytic cracking?

cracking requiring high temperature (500C), not as high as steam cracking and mixed with a catalyst (aluminium oxide)

What makes catalytic cracking more economical?

catalyst speeds up reaction- less energy required, faster process, higher yield of short chain hydrocarbons

What are properties of alkanes?

saturated, contains only single bonds, cannot make any new bonds

What are properties of alkenes?

unsaturated, contains double carbon bonds, can make new bonds- double bond can become 2x single bonds

What doe saturated mean?

cannot form new bonds

How to test for the products of cracking?

Bromine water

How does the bromine water change when alkenes (product of cracking) are present?

alkene present- change to colourless, as alkene reacts with bromine

alkene not present- remains orange, no alkene to react with bromine water

What if a fuel?

processed fractions of hydrocarbons

What are examples of fuels from hydrocarbon?

petrol, diesel oil, kerosene (jet fuel), LPG (liquified petroleum gas)

What does volatile mean?

how easy a substance vapourises

What are short chain hydrocarbons properties?

high flammability, low boiling point, less atoms, low viscosity

What are long chain hydrocarbons properties?

Low flammability, high boiling point, high viscosity, more atoms

What is the use of petrol?

fuel for cars

What is the use of diesel?

fuel for cars, vans and lorries

What is the use of naphthla?

manufacturing of chemicals

What is the use of kerosene?

aircraft fuel

What is the use of bitumen?

used for road surfacing

What is the chemical reaction for the complete combustion (with enough oxygen) of a hydrocarbon?

hydrocarbon + oxygen -> carbon dioxide + water

What is the chemical reaction for the incomplete combustion (without enough oxygen) of a hydrocarbon?

hydrocarbon + oxygen -> carbon monoxide + carbon + water

What is feedstock?

raw materials to supply or fuel a machine or industrial process

Where is feedstock used?

the petrochemical industry (petroleum), used to make solvents, lubricants, polymers, and detergents.

Why are alkenes good for making compounds and polymers?

more reactive due to being unsaturated, double C bond can break and add other molecules into it. Therefore it can be used as a starting material

Why are alkenes unsaturated?

They contain 2 fewer hydrogen atoms than alkanes with the same number of carbon atoms

What is a homologous series?

a sequence of compounds with the same functional group and similar chemical properties

What is a functional group?

a group of atoms that give organic compounds their characteristic reactions

What is the functional group of alkenes?

double carbon bond

What is the first 4 alkenes?

Ethene, propene, butene, pentene

What is the molecular formula and structural formula for ethene?

C2H4

What is the molecular formula and structural formula for propene?

C3H6

What is the molecular formula and structural formula for butene?

C4H8

What is the molecular formula and structural formula for pentene?

C5H10

What happens in the combustion of alkenes?

carbon dioxide and water produced. it is better used as feedstock- being the starting point for many chemicals

What happens in the addition reaction of alkenes?

molecules added across the C=C bond, two materials add together to become one (addition of two), useful as feedstock as it will react with other substances

What happens in the addition reaction of alkenes with hydrogen?

alkenes is unsaturated, meaning it can form a saturated hydrocarbon with H2.

What is the reaction between hydrogen and alkenes?

Alkene + Hydrogen -> Alkane

What is the reaction between hydrogen and alkenes called?

Hydrogenation

What happens in a reaction between halogens and alkenes?

the halogen bonds to both of the carbon atom

What is the name of the compound formed between halogens and alkenes?

halogenoalkane

What halogens can react with alkenes?

Chlorine, Bromine or Iodine

What is the reaction between halogens and alkenes?

halogens + alkene -> dihalogenalkene

What is the reaction between water (steam) and alkenes?

reaction is called hydration which requires heat, pressure and catalyst

What is the formula for the reaction between water (steam) and alkenes?

Alkene + steam

What are the first 4 alcohols?

Methanol, ethanol, propanol, butanol

What is the functional group of alcohols?

OH

What is the chemical formula and structural formula for methanol?

CH3OH

What is the chemical formula and structural formula for ethanol?

C2H5OH

What is the chemical formula and structural formula for propanol?

C3H7OH

What is the chemical formula and structural formula for butanol?

C4H9OH

what are the two ways to make ethanol?

hydration or fermentation

What is needed for hydration to make ethanol?

steam, high temperature and a catalyst is required.

What is the formula for making ethanol via hydration?

Ethene + water -> Ethanol

C2H4 + H2O -> C2H5OH

What is needed for fermentation to make ethanol?

yeast. room temperature, a few days

What is the formula for making ethanol via fermentation?

Glucose -> ethanol + carbon dioxide

C6H12O6 -> 2C2H5OH + 2CO2

What are the advantages of hydration to make ethanol?

fats, less labour intensive, doesn't require CO2, continuous process, pure ethanol made, no waste product, catalyst can be reused

What are the disadvantages of hydration to make ethanol?

needs a catalyst, high energy, expensive, fossil fuels to generate electricity- uses crude oil- non renewable,

What are the advantages of fermentation to make ethanol?

doesn't require high temperature, lower costs to make, easy, low energy, sugarcane (glucose) is renewable, absorbs CO2 - doesn't contribute to global warming, lots of yeast avaliable

What are the disadvantages of fermentation to make ethanol?

takes a long time, less safe as yeast is more difficult to control and can form bacteria, CO2 as waste product, sugar cane (glucose) has to be grown- uses land, many steps, only 50% pure- steps needed to separate ethanol

What happens in the combustion of alcohol?

alcohols are flammable, allowing it to be used as fuel, it burns with a clean blue flame

What is the reaction for the complete combustion of alcohol?

Ethanol + oxygen -> carbon dioxide + water

What happens in the reaction between sodium and alcohol?

produce alkaline solution, no flame, effervescence, less vigorous than Na + H2O

What is the reaction between sodium and alchol?

Sodium + ethanol -> sodium ethoxide + hydrogen

What happens in the oxidation reaction of alcohol?

reacting alcohol with oxidising agent to oxidise alcohol- different oxidising agents produce different products. Also happens happens if exposed to air, microbes in air porduce carboxylic acids

What is the formula for the oxidation reaction of alcohol?

alcohol + oxygen from agent -> carboxylic acid + water

What are the properties of alcohol?

soluble in water, pH7, flammable, good solvents, higher boiling points similar alkanes

What are the uses of alcohol?

fuel, food + drink, sanitising, disinfectants

What are the first 4 carboxylic acids?

Methanoic acid, ethanoic acid, propanoic acid, butanoic acid