diffusion Flashcards
hydrochloric acid vapour and ammonia paper
- ammonia is lighter as it has a lower Mr which means it will move faster
- ammonia particles bounce of air particles which is why it does not diffuse as quickly
% oxygen in the air
- as the copper is heated the air from the syringe is passed between the pieces of copper to the second syringe and then back again
- this process is repeated until there is no further change in the volume of the gas syringe
- formed black copper oxide
- the copper reacted with oxygen in the air taking 20% of the air. this decreases the column in the syringe by 20% to 80cm
what is in air
- 20% oxygen - very reactive - medical uses and making steel
- 78% nitrogen - unreactive, used for freezing food, packaging meat and crisps
- 0.03% CO2 - unreactive- fire extinguishers
- 1% noble gases - e.g. argon - very unreactive- light bulbs, neon lights
fractional distillation of air
1) air is cooled to -200% and condenses into a liquid
2) co2 and water are removed as solids before fractional distillation takes place
3) this is done by compressing or squashing the air and the use of cold water
4) nitrogen boils at -196 degrees centigrade so it can be removed from the top of the column as a gas
5) at -185 degrees oxygen is still a liquid so can e taken out the bottom of the column
6) warmer at the bottom
burning elements
magnesium- bright white flame
carbon - glows orange
iron- bright white sparks
sodium- intense orange
testing oxide compounds
1) place 2cm(3) samples of each oxide and water solution into seperate tesst tubes
2) add 3 drops of ui solution. observe the colour of the indicator in each sample
3) record results in a suitable table:
carbon dioxide - light yellow
calcium- dark blue
phosphoruus - pink
nitrogen - pink
potassium - dark blue
sulfur - red
sodium - dark blue
pollution issues from burning fuels
so2
- combustion of fuels containing s
- causes acid rain
- solution : desulfurisation
pollution issues from burning fuels
nitrogen oxides
- car exhausts
- adds to global warming / acid rain
- solutions: use biofuels / electric cars
pollution issues from burning fuels
unburned fuels
- some fuels do not burn
- wastes fuel
- solution- ensure engine is well tuned
pollution issues from burning fuels
carbon monoxide
- incomplete combustion
- prevents enough oxygen from being carried around the body
- solutions: ensure there is a good supply of air when burnt
pollution issues from burning fuels
parrticulates
- incomplete combustion of fuels containing c
- global dimming
- ensure there is a good supplyy of air when burnt
diffusion
- the automatic mixing of liquids and gases as a result of the random motion of their particles
- diffusion is slower in cold water as there is less energy so particles move slower
- diffusion is faster in hot water as the particles have more energy as so move faster
