Chemistry C1

Created by: aliceinwonderland2000
Created on: 07-02-16 16:41

Why are fossil fuels finite resources?

Because they are no longer being made, or are being made very slowly

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What is a non renewable resource?

When the resource is being used up faster than it is being produced

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What difficulties are associated with the finite nature of crude oil?

all the readily extractable resources will be used up, so replacements need to be found

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What is crude oil?

A mixture of many different oils that are all hydrocarbons

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What is a hydrocarbon?

An atom made from molecules of hydrogen and carbon ONLY

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Name the oils, in order in the fractioning column

LPG, petrol, paraffin, diesel, heating oil, fuel oils, bitumen

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Why can crude oil be seperated?

because the hydrocarbons all have differently sized molecules

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Why do bitumen and other heavy oils have high boiling points? where would they exit the fractioning column?

Because they have strong forces of attraction, so a lot of energy is needed to break the forces inbetween. They would exit at the bottom of the fractioning column

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What problems are associated with transporting oils?

oil slicks can damage bird's feathers, and the clean up operations use detergents which can harm wildlife

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What are the political problems?

The prices can be high and cause problems for the future supply on non-oil producing nations

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What fraction is in high demand for uses like medicines ,plastics and dyes?

naphtha

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What is cracking?

When large alkane molecules are turned into smaller alkane and alkene molecules.

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What is useful about alkene molecules?

They have a double bond, so it can be used to make polymers

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Why are more fossil fuels being burnt?

Becuase of the increase in population

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Why are governments concerned about this?

Because of large amounts of carbon dioxide emmisions

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What does burning hydrocarbons in air produce?

carbon dioxide and water

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What is the word equation for this?

methane + oxygen - carbon dioxide + water

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What is complete combustion?

when a fuel burns in plenty of air

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What is incomplete combustion?

When a fuel burns in little oxygen

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Why is complete combustion better?

Because more energy is released than in incomplete combustion

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What is made in incomplete combustion

Carbon monoxide and carbon(soot)

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What is the word equations for incomplete combustion?

fuel+oxygen-carbon monoxide+water OR fuel+oxygen-carbon+water

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What is the symbol equation for complete combustion? (methane)

CH4 + O2 → CO2 + H2O

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What is the symbol equation for incomplete combustion? (methane)

CH4 + O2 → C + 2H2O OR 2CH4 + 3O2 → 2CO + 4H2O

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What is clean ar made of?

(78%) nitrogen (21%) oxygen (0.035%) carbon dioxide

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Why do these percentages change very little?

Because the processes are balanced that use up and make carbon dioxide and oxygen

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Why has the amount ofncarbon dioxide in the air increased over time?

deforestation, and because of the increased population

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What formed the original atmophere?

gases that escaped drom the interior of the earth.

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How did the oxygen reach its current levels?

Because of photosynthesis

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What is the process called degassing?

the process of gases coming from the center of the earth through volcanos

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Nameand explain one theory about the original atmosphere

atmosphere was originally rich in water vapour and carbon dioxide. The vapour condensed into oceans, the carbon dioxide dissolved in the water. Nitrogen levels increased, little was removed because is unreactive. organisms evolved to photosynthesise.

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Why is it important to control atmospheric pollution?

Because it can affect people's health and the enviroment

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Why is sulfur dioxide dangerous?

because it can cause breathing difficulties for people with asthma, and can cause acid rain that damages wildlife and limestone buildings

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What does a catylic converter do?

changes carbon monoxide into carbon dioxide

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What chemicals react in a catylic converter?

nitric oxide, and carbon monoxide

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What gases are formed afterwards?

nitrogen and carbon dioxide

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What is an alkane?

hydrocarbons that only have single covalent bonds

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What is an alkene?

hydrocarbons that have double covalent bonds between carbon atoms

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What is used to test for an alkene?

Bromine

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What happens if the test proves the chemical is an alkene?

It will become colourless

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What bonds do saturated fats have?

single covalent bonds only

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What bonds do unsaturated fats have?

at least one double covalent bond

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What is addition polymeristaion?

The process where many alkene monomers react to produce a polymer

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How can you recognise a polymer from its displayed formula?

The chain is long, brackets at either end with extended bonds, the letter"n" after the brackets

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What are the properties of nylon?

tough, lightweight, keeps water and UV light out

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What two typesof polymers are scienctists developing?

bio-degradable, and dissolvable polymers

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Why is research into polymers important?

because of the envirometnal and economic issues associated with them

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How are atoms in polymers held together?

Strong covalent bonds

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What plastics have low melting points?

Those with weak intermolecular forces

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What plastics have higher melting points?

those that have strong covalent bonds or cross-linking bridges

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What happens when protein molecules is some foods are heated?

They become denatured

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Why does the texture change?

Because the shapes of the proteins change permenantly

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Why are carbohydrates easier to digest when they have been cooked?

The starch grains swell and spread out, and the cell walls rupture which produces a softer texture

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What is the scientific name for baking powder?

sodium hydrogencarbonate

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What does sodium hydrogencarbonate give off when heated?

carbon dioxide

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What is the word equation for the decomposition of sodium hydrogencarbonate?

sodium hydrogencarbonate → sodium carbonate + carbon dioxide + water

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What is an emulsifier?

Molecules that help to bind water and fat or oil together

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Which part of an emulsifier is hydrophillic?

The head

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Which part of an emulsifier is hydrophobic?

The tail

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How do they work?

The hydrophillic head combines with the water, and the hydrophobic tail combies with the oil or fat

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What is produced when an alcohol reacts with an acid?

An ester and water

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What are esters used for?

Making perfume

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What experiment can be used to make an ester?

The acid is added to the alcohol and heated for some time. The condensor stops the ga from escaping and helps to cool it down again so it can react more. The condensor allows the reaction to continue for longer

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What properties must a perfume have?

Must be non reactive, non toxic, non irritable and be insoluble in water

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What is a solution?

mixture of a solvent and a solute

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Explain the evaporation of perfumes in terms of kinetic theory

to evaporate, the particles need kinetic energy to overcome attraction to other particles. The attraction between them is very weak, so it is easy to evaporate

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Why doesn't water dissolve nail polish?

The attraction between the water molecules is stronger than that between the water molecules and the nail polish molecules. The attraction between the nail polish molecules is stronger in that between the nail polish molecules and the water molecules

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What is a colloid?

A paint where the particles are mixed and dispersed with particles of a liquid, but are not dissolved

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Why wont the components of a colloid seperate?

Because the particles are dispersed throughout the mixture, and are small enough not to settle at the bottom

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Most paints dry because...?

It is applied in a thin layer, and the solvent evaporates

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How do emulsion paints dry?

The solvent evaporates