Chemistry Unit 1
- Created by: hannahlouisepark
- Created on: 18-05-17 09:49
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- C1
- using carbon fuels
- choosing fuels
- amount of fossil fuels being burnt is increasing because populations increasing
- a fuel is chosen because of its key features: energy value, toxicity, cost, storage, pollution caused and ease of use
- governments are becoming concerned because CO2 emissions are increasing when fossil fuels are being burnt
- combustion
- complete combustion occurs when a fuel burns plenty of oxygen
- balanced equation for incomplete combustion: 2CH4 + 3O2 --> 2CO + 4H2O OR CH4 + O2 --> C + 2H2O
- balanced equation for complete combustion: CH4 + 2O2 --> CO2 +2H2O
- word equations for combustion are: fuel + oxygen --> carbon monoxide + water OR fuel + oxygen --> carbon + water
- toxic gas (carbon monoxide) and soot (carbon) are made during incomplete combustion
- choosing fuels
- design polymers
- disposing of polymers
- recycling is difficult
- scientists are discovering new polymers that dissolve and are biogradeable polymers
- research into new polymers is important as there are environmental and economic issues within the use of existing polymers
- disposal by burning makes toxic gases and wastes crude oil
- wasting land that could be used valuble for other purposes
- breathable polymers
- poly eurathane membrane it too fragile on its own so its laminated onto nylon to make a stronger fabric
- GORE-TEX(r) material is waterproof and yet breathable, has all properties of nylon
- nylon is tough, lightweight, keeps out water and keeps UV out but does not let water through
- disposing of polymers
- making crude oil useful
- problems in extracting crude oil
- demand of oil is very high, there is conflict between needs for making petrochemicals for fuels
- transportation can cause oil slicks, damaging wildlife
- may be political problems relating to the extraction of crude oil
- fossil fuels
- there are specific difficulties associated with the finite nature of crude oil and finding replacement
- non-renewable as they are being made up faster than they are being formed
- finite resources as they are no longer being made or they are but very slowly
- fractional distillation
- crude oil can be separated because the hydrocarbons in fractions have different sized molecules
- high boiling point like bitumen go at the bottom of the fractional column, where low boiling points like LPG go at the top
- crude oil is a mixture of many types of oil, which are all hydrocarbons
- crude oil is heated at the bottom of a fractioning column
- cracking
- process turning large alkane into smaller alkaneand alkene molecules
- helps oil manufactures match supply with demand
- problems in extracting crude oil
- cooking food additives
- baking powder
- word equation for decomposition of sodium hydrocarbon ate: sodium hydrocarbonate --> sodium carbonate + carbon dioxide + water
- when it is heated it breaks down(decomposes) to give carbon dioxide
- symbol equation for decomposition of sodium hydrocarbon ate: 2NaHCO3 --> Na2CO3 + CO2 +H2O
- sodium hydrocarbonate
- emulsifiers
- are molecules that have amwathr loving part and an oil loving part
- water end (headl) of emulsifying molecule is hydrophilic
- oil end(tail) of emulsifying molecule is hydrophobic
- help keep oil and water from separating
- proteins and carbohydrates
- a potato is a carbohydrate, which is easier to digest when cooked as starch swells up and spreads out; cell wall ruptures
- texture of egg/meat changes when cooked because shapes of protein change permanently
- protein molecules in eggs and eat permanently change shape when cooked - denaturing
- baking powder
- clean air
- the atmosphere
- overtime, organisms that could photosynthisise evolved and converted carbon dioxide and water into oxygen
- gases come through centre of earth by volcanoes- degassing
- gases escaping from the interior earth formed the original atmosphere
- pollution control
- sulfur dioxide i a pollutant that can cause difficulty for people with asthma
- a car fitted with a catalytic converter changes carbon monoxide into carbon dioxide
- in a catalyst converter, a reaction takes place on the surface of the catalyst. the gases formed are in natural air: nitrogen and carbo dioxide
- important to control as of the effects on health, natural environment and built environment
- what is in air?
- over last few centuries, percentages of carbon dioxide has grown because of increased population and deforestation
- 71% nitrogen 21% oxygen 0,035% carbon dioxide
- there is a balance between the carbon cycle that use up and both make carbon dioxide and oxygen
- the atmosphere
- paints & pigments
- phosphorescent pigments
- much safer than older alternative radioactive paints
- they glow in the dark because they absorb and store energy and release it as light overtime
- paint drying
- oil paints dry as solvent evaporates and is oxidised
- emulsion paints are waterbed that dry when solvent evaporates
- most paints dry as they are applied with a thin layer, solvent evaporates
- colloids
- components will not seperate as particles are separated and dispersed through mixture and are small
- paint is a colloid where particles are mixed and dispersed with particles of a liquid
- thermocrhomic pigments
- change colour at different tempeatures
- can be added to acrylic paints to make even more colour changes
- phosphorescent pigments
- smells
- perfume properties
- must be non-toxic
- must evaporate easily
- must not react with water
- not to irritate skin
- must be insoluble in water
- esters
- alcohol + acid --> ester + water
- used to make perfume
- made by : adding acid to alcohol, condenser stops gas from escaping to cool down again, so can react more and go on for loner
- alcohol reacts with acids to make ester and water
- solutions
- esters can be used as solvents
- is a mixture of solvent and solute, doesn't separate out
- perfume properties
- making polymers
- polymerisation
- polymers have long chains
- addition polymerisation needs a high pressure and a catalyst
- involves the reaction of many unsaturated alkenes ( monomer molecules)
- addition polymerisation reaction has a long chain, caused the double bonds to break and from new bonds
- hydrocarbons
- alkanes have a single bond: CnH2n+2
- a saturated compounds only single bonds
- made up of ONLY hydrogen and carbon atoms
- unsaturated compound has at leat one double covalent bond
- bromine is used to test for alkene. when orange bromine is added , alkene decolourises the bromine to be colourless
- alkenes have a double bond : CnH2n
- polymerisation
- using carbon fuels
- combustion
- complete combustion occurs when a fuel burns plenty of oxygen
- balanced equation for incomplete combustion: 2CH4 + 3O2 --> 2CO + 4H2O OR CH4 + O2 --> C + 2H2O
- balanced equation for complete combustion: CH4 + 2O2 --> CO2 +2H2O
- word equations for combustion are: fuel + oxygen --> carbon monoxide + water OR fuel + oxygen --> carbon + water
- toxic gas (carbon monoxide) and soot (carbon) are made during incomplete combustion
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