AQA combined chemistry paper 2 Foundation

Mixture

Not pure. Different compounds/ not elements chemically bonded.

Compunds containing only hydrogen and carbon

Hydrocarbon

Fossil fuel mixture of hydrocarbons

Crude Oil

Seperating liquid from a mixture by evaporation or condenstaion

Distillation

Two or more different elements chemically bonded

Compound

Two or more atoms chemically bonded

Molecule

Hydrocarbons with similar boiling points separated from crude oil.

Fractions

Hydrocarbobns with only single covalent bonds eg, C-C

Alkanes

Known as saturated hydrocarbons

• Methane CH4

• Ethane C2H6

• Propane C3H8

• Butane C4H10

Seperating liquids from a mixture by boiling then condensing at different temperatures.

Fractional Distillation

Hydrocarbon + Oxygen -> Water + Carbon Dioxide

Burning Hydrocarbons

Oxygen added or electrons lost

Oxidised

When a fuel burns with insufficient oxygen. Produces toxic Carbon Monoxide (CO)

Incomplete combustion

Breaking large alkanes into smaller, more useful ones.

Cracking

Breaking down a compound by heating it

Thermal decomposition

Chemical which speeds up a reaction without being used up itself. In industry the increase rates of reaction and reduce energy cost.

Catalyst

Hydrocarbon with a double covalent bond C=C

Alkenes

Known as unsaturated hydrocarbons

Has twice as many H as C atoms

picture attatched is Ethane

Unsaturated hydrocarbons turn Bromine water colourless

Testing for alkenes

In a chemical reaction the total mass of reactants = total mass of products

Conservation of Mass

How fast reactants turn into products

Rate of Reaction

1. Measure decrease in mass of a reaction if a gas is given off.

Measuring rate of reaction

2. Increase in volume of gas given off. Catch gas given off

3. Decrease in light passing through a solution

The steepness of the line at any point on a reaction vs time graph.The steeper the line on the reaction vs time graph, the faster the reaction.

Calculating rate of reaction

Increases speed and energy of particles

Increasing temperature

Amount of a substance per defined volume units of mol/dm`3

Concentration

Reaction that absorbs in energy

Endothermic

Reaction that releases heat energy

Exothermic

Concentrations remain constant

Equilibrium

Reactions occur when particles collide with enough energy

Collision Theory

Minimum energy needed in a collision for a reaction to occur

Activation Energy

A reaction where the products will turn back into the products

Reversible Reactions

Made of one substance. Can be an element or compound.

Pure

A miture designed to produce a useful product.x

Formulation

Examples: paints, washing liquids, fuels, alloys, fertilisers, cosmetics

A seperation technique where a solvent moves up a material and carries different substance up different heights with it.

Paper Chromotography

Hydorgen makes a squeaky 'pop' when lit with a splint.

Test for hydrogen

Oxygen will relight a glowing splint

Test for Oxygen

If you bubble Carbon Dioxide through limewater it will turn milky (cloudy white)

Test for Carbon Dioxide

Will turn blue litmus paper white. Need to be very careful as the gas is toxic (poisonous)

Test for Chlorine Gas

Volcanoes released Carbon dioxide, water vapour and nitrogen. Similar to Mars and Venus.

Earths early atmosphere theory

Coal, crude oil and natural gas. Formed from fossilised remains of plants and animals.

Fossil Fuels

Carbon stored in shells and skeletons tuned into limestone. Carbon in living things was also locked away as fossil fuels.

Carbon 'locked into' rock

Removed from atmosphere by reactions with oxygen.

Ammonia and Methane

Nitrogen: 78%

Earths Atmosphere today

Oxygen: 21%

Argon: 0.9%

Carbon Dioxide: 0.04%

Trace amounts of other gases

stops heat escaping from the Earth into space. This results in the earth getting hotter.

Greenhouse Effect

1. Carbon Dioxide: released from burning fossil fuels.

Greenhouse Gases

2.Methane: released from swamps, rice fields.

3. Water vapour (eg steam and clouds)

1. Rising sea levelsas a result of melting ice caps.

Risks of global climate change

2. Extreme weather eg storms.

3. Changes to weather and rainfall patterns.

4.Ecosystems under threat

Released by burning fossil fuels.Causes acid rain and breathing issues.

Nitrogen Oxide

Released by burning fossil fuels. Causes acid rain.

Sulfur Dioxide

Water that is safe to drink. Not pure as it contains dissolved substances.

Potable Water

No dissolved subsances. Only H2O

Pure Water

Breaking down a substance in a liquid using electrolysis.

Electrolysis

A more reactive metal will displace a less reactive metal.

Displacement