Aqa As Chemistry 7404/2 Paper 2 Organic And Physical Chemistry Question Paper + Mark Scheme [Merged] June 2023

Explain how paper chromatography separates mixtures? {Ans: As the solvent moves up the paper it carries the mixtures substances with it. Different components of the mixture will move at different rates. Depending on their solubility to the solvent and attraction to paper . This separates the mixture out.}Explain how deposits of limestone , call and crude oil are formed ? {Ans: - tiny marine life die and fall to seabed buried in mud over millions of years they are exposed to high temperatures and pressure}Describe and explain how the surface of the early earth and its atmosphere have changed to form the surface of the Earth and its atmosphere today? (6) {Ans: oxygen increased because plants and algae developed and used carbon dioxide for photosynthesis producing oxygen; carbon dioxide decreased because of this • carbon dioxide decreased because oceans formed and absorbed carbon dioxide; carbon dioxide became locked up in sedimentary • oceans formed because the water vapour cooled and water vapour in the atmosphere condensed • which formed the separate continents • nitrogen had formed because of ammonia in earths early atmosphere reacted with oxygen volcanoes reduced because the Earth cooled forming a crust}Explain the effect