aqa chemistry gcse june 2016Watch
1) Electron shell: 2,3( 1 mark) Nucleus( 1 mark) Neutron is uncharged, proton has a charge of +1 ( 3 marks) Not in form 2,8,8, has 1,8. Neon has 10 electrons, the structure had 9 electrons, doesn't have a full outer shell but neon does (3 marks)
2) Tick box: copper oxide(1) 20.3(2 marks) Digital thermometer, more precise and not subject to human error Beaker insulated( any forms of insulation: lid, wool (2) Carbon particles produced( particulates) incomplete combustion(2) Best fuel because it produces least smoke. Produces the most energy per g(2)
Advantages of hydrogen:
Renewable Provides more energy No co2 released Disadvantages: Hydrogen is explosive Hard to store because it is a gas
Thermal decomposition(1) Question on potassium carbonate: doesn't thermally decompose, co2 not released, Bunsen burner temperature is not high enough( 3 marks) Reactivity question: the lower the metal on the reactivity series, the easier it is broken down(2)
Conditions for cracking: high temperatures/400-700 degrees and a hot catalyst (2 marks) Fermentation question: sugar is dissolved and yeast is added to make ethanol(2) Ethanol question: ethene is reacted with steam at high temperatures and catalyst(2) Advantages and disadvantages of crude oil vs plants:
Crude oil is a continuous process so faster. Crude oil is more widely available Non renewable, co2( global warming) (4 marks)
metal ores are ores which contain enough of the metal to be worthwhile extracting( 1 mark) It is converted to steel because cast iron is brittle or to make it stronger Steel has more uses Corrosion resistant ( 2 marks) 2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks) It is not sent to landfill because this takes up space and causes pollution 3 marks) Question on distillation: Heat mixture between 80-99 degrees, the ethanol evaporates, cools and condenses to form pure ethanol and then raise temperature to 100 when all ethanol has evaporated to do the same to water. ( 3 marks). Question on carbon neutral/global warming: carbon dioxide is a greenhouse gas This takes up CO2 when it grows in photosynthesis The same amount is released when biofuel or oils are burned So no overall increase in CO2 (3)
Last question on hydrogenation; 60 degrees, reacted with hydrogen, nickel catalyst, double bonds converted into single bonds, increasing melting point, done so that's it's a solid at room temperature for a thick, spreadable consistency (5)
Mark somewhere for completing drawing of the alkane(1) Bromine goes colourless somewhere(1) Clear is not acceptable.
CREDIT TO @science fanatic or something.