wrong chemistry paper 2

uses of methylated spirit

• fuel

• solvent

• antiseptic

why its better if less sulfur

• sulfur reacts with oxygen to form sulfur dioxide

• so less sulfur dioxide emitted

• so les acid rain

• so less limestone reacts with acid rain

if cube x10 bigger surface area

surface area to volume ratio decreases by a factor of 10

structure of DNA

• two polymer chains

• four different monomers

• double helix

if increase of ions on left side

• equilibrium moves to the right

• to the increase in concentration of ions is reduced

if temp increas

• equilbiurm moves to the left

• so the temperature is reduced

• therefore the forward reaction is exothermic

why sometimes no change in equilibrium if pressure change

• no change in equilibrium position

• as no gases are present

how to decrease rf value

• allow to solvent front to travel further

• use a different solvent

how is ethanol produced from sugar solution

• fermentation

• add yeast

• anaerobic conditions

gas produced when sodium added to ethanol

• hydrogen

processes led to changes

• volcanic activity released water vapour

• condensed to form oceans

• carbon dioxide dissolved in oceans

• carbonates produce sediments

• carbon locked up in sedimentary rocks

• algae and green plants evolved

• absorb carbon dioxide by photosynthesis which then released oxygen

• carbon locked up in fossil fuels

why is solution cloudly

• sulfur formed

• which is a precipitate

investigate, connotation of sodium thiosulfate affects the rate of reaction

• measure volume of sodium thiosulfate

• place in conical flask

• measure volume of hcl

• place on cross

• add hcl to flask

• swirl

• stop stopwatch

• measure time for cross to become no longer visible

• repeat and find mean

• repeat for different concentrations of sodium

• control

  • conc and volume of hcl

  • total volume of sodium thiosulfate solution

evaluate suitability of polypropene and polyester

• advantages of polyester

  • better flame resistance

  • higher melting point

  • absorbed water so less likely to ignite

• disadvantages

  • high density, so heavy

  • absorbed water, gets wet and become heavy

how carbon monoxide is produced when petrol is burned in car engines

• incomplete combustion

• as insufficient oxygen supply

why max allow % of carbon monoxides has been decreases

• greater public concern/ awareness

• more cars so otherwise there would be more carbon monoxide entering atmosphee

• improve engine technologu

• catalytic converter have been introduced

how oxides of nitrogen are produced when petrol is burned

• nitrogen from atmosphere reacts with oxygen

• at high temperature in engine, or with a spark from spark plug

compare use of coated paper compared with polystryene to make disposable cups

• raw materials

  • crude oil finite

  • wood renewable

  • wood involves land use and may involve deforestation

• manufacturing

  • both required energy which may be derived from fossil fuels

  • paper more energy intensive

  • need for more energy for paper potentially release more carbon dioxide

  • paper involved higher water usage, so increase the potential for water pollution

  • paper cups heater to transport, so higher energy requirement

  • packaging requirements similar

paper and polystyrene usage and disposal

• usage

  • both single use, so neither has an advantage

• disposal

  • paper release more energy if incinerated, so more energy can be used for other purposes

  • paper will decompose

  • polystyrene could resale toxins on incineration, and won’t decompose, but can be used to manufacture other products

  • both can cause litter or visual pollution

titan has methane, ho this gg keeps titan warm

• methane allows shorter wavelength radiation to pass through from the sun

• which is re-emitted from the surface as longer wavelength radition

• which is absorbed by methane in the atmosphere

if no oxygen, why these organisms couldn’t have evolved in the same way as on earth

• no oxygen

• so photosynthesis hasn’t occured

• so little carbon dioxide present,

  • oxygen using animals cannot have evolved on titan

why don’t aluminium window frames corrode after they are made

• aluminium has a coating og aluminium oxide

• so the aluminium oxide protects the metal from further corrosion

explain why diesel oil collects above heavy fuel oil but belo kerosene in the fractionating column

• diesel oil has a lower boiling point than heavy fuel oil

• but diesel oil has a higher boiling point than kerosene

apparatus to find the rate of production of a gas

• gas syringe

• stopwatch

three conclusions from graph

• rate decreases

• rate decreases more slowly as time increases

• rate becomes zero at 60s

magnesium over steel ships, how does this prevent steel from rusting

• magnesium is more reactive than iron

• so magnesium provides sacrificial protection

explain the process by which carbon monoxide can be produced when methane is burned

• not enough oxygen

• so incomplete combustion

what are glass fibres

• a reinforcement

why is an outer skin added to the polystyrene core

• to make the thing

  • harder, stronger, tougher, more rigid, waterproof

find total mass of dissolved solids in 100cm

• weigh evaporating basin

• add mesa volume of water

• weight again

• heat to evaporate water

• reweigh

• repeat heating until constant mass obtained

• subtract mass of basin from mass

• repeat and calculate a mean, discarding anomalous results

• calculate the mass in 100cm3 water if necessary

why don’t you put polymer with copper about tone melted

• copper produced out be impure now

why is recycled scrap better

• uses less energy

• conserve copper

• produces less waste

why did mass decrease

• water vapour was produced

• so water vapour escaped from the tube

gass and bottles, LCA’S

• manufacturing, glass is heavier so takes more energy to tranasport

• use and operation, reuse of glass conserve resources, but consumes energy and water during washing

• disposal, reduce use of landfill and use less energy than making new ones

how does treatment of sewage work

• screening/grit removal

• sedimentation to produce sewage sludge and effluent

• anaerobic digestion of sludge

• aerobic biological treatment of effluent

why aren’t ions stopped

• ions pass through the filter

• because the ions are in solution

ground water,

• contains microbes which are harmful

• so the water is sterilised

why is drinking water called pure

• the water is unadulterated/in its natural state

why only ammonia collected

• mixture is cooled

• so that only ammonia liquefies

yield of caber process

• higher temperature gives higher rate as more particles have the AE

• use of catalyst gives higher rate because the AE is lowered

• use of catalyst has no effect on the position of equilibrium

• higher temperature, uses more energy so increases cost

• higher pressure, required stronger reaction vessels so increases costs

• catalyst reduces energy costs