Chemistry paper 2 practicals

• rate of reaction :

  • hydrochloric acid plus+sodium thiosulphate causes solution to go cloudy measure time for cross to disappear repeat at different temperature

  • measure volume of gas produced by attaching gas syringe to reaction Vessel
• Fractional distillation

  • the crude oil is heated to a high temperature so that all compounds evaporate from liquid to gas

  • the hot gaseous hydrocarbons rise up the column

  • the hydrocarbons will condense when they become cooler than their boiling point

  • the longer chains condense at the bottom because they have high boiling points

  • the shorter chain condense at the top because they have lower boiling points
• Catalytic Cracking :

  • heat the long hydrocarbons to vaporise them

  • the vapour is passed over a hot powdered aluminium oxide catalyst

  • the molecules split apart on the surface of the specs of catalyst
• Steam cracking :

  •vaporise the hydrocarbon

  •mix them with steam and heat then to a very high temp
• Gases :

  Chlorine -bleaches damp litmus paper turning it red then white.

  Oxygen- if you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the splint.

  Carbon dioxide-bubbling co2 through an aqueous solution of limewater causes the solution to turn cloudy.

  Hydrogen-hold a lot splint at the open end of a test tube containing h2 you’ll get a squeaky pop
• Atmosphere:

  • volcanic activity gave out nitrogen water vapour and small amounts of methane and ammonia

  • when water vapour in the atmosphere condensed it formed oceans. Lots of CO2 was removed from the atmosphere as it dissolved into the oceans.

  • green plants and algae produced oxygen by photosynthesis today the atmosphere contains 80% nitrogen 20% oxygen and small amounts of other gases
• Copper extracting :

  •Bioleaching - bacteria are used to convert copper compounds into soluble copper separating out the copper from the wall the leach it contains copper irons which can be distracted by electrolysis or displacement
• copper extracting:

  phytomining- involves growing plants and soil that contains copper which will build up in the leaves. The plant can be harvested dried and burn in the furnace. The ash contains soluable compounds which can be extracted by electrolysis or displacement