As level chemistry coursework plan help?

Question

i have been off school all week with illness and my chemistry teacher has set this and says that it is completely research based, but i cant find anywhere that will help! the question is 'copper has two oxides, Cu2O and CuO.
copper carbonate, CuCO3 decomposes on heating to form one of these oxides and an equation can be written for each possible reaction:
equaton 1: 2CuCO3(s) ---> Cu2O(s) +2CO2(g) + 1/2O2(g)
2: CuC03(s) ---> CuO(s) + CO2(g)
using ideas learnt about mole, plan and desgn an experiment to measure a volume of gas that will prove with of the two equations is correct' and i have to include equipment needed, quantities of any reagents used, any special sets of conditions required for a particular procedure, and a detailed method which provides full instructions and any precautions.

my first thought was to put the copper carbonate in a conical flask heat it untill gas is given off then displace water in a conical flask to collect it? does that sound right?

Answer 1

I like to measure the volume of gases using a gas syringe! If you know the amount of reactant (copper carbonate) you will know the number of moles of gas evolved using the rule that at STP 1 mole of gas has a volume of 24dm3 (that's 24000 cm3) so if you have 0.001 mole of carbonate you would expect 0.0025 moles of gas in equation 1 (24 cm3) and 0.001 moles of gas in equation 2(60cm3). A up turned measuring cylinder in water is not accurate enough, a burette might be but a ga syring is just easier all round.

PS As an A level chemistry teacher I shouldn't have done this for you so don't tell anyone ok!

Answer 2

Would the two different possible pathways give different amounts of gas per gram of starting material? If so, why?

How could you set up your apparatus to measure the volume of gas evolved? (it sounds as if you are certainly on the right track here)

Going a little bit beyond the question, can you think of a way of absorbing the carbon dioxide gas formed, seeing if any other gas is formed at the same time, and testing to see if it is oxygen?

Answer 3

Badgergirl and Dr jaycat Do remember that temperature affects the volume of a fixed mass of gas' 1 mole of a gas is 22.4 dm3 at stp but that translates using the gerneral gas equation to near enough 24 dm3 at room temperature and usual pressures. Good enough for GCSE work. - ex chem teacher

Answer 4

For BAdgergirl...as you claim to be an AS level chemistry teacher I would hope you know that at STP 1 mole of anny gas occupies 22.4 L, not 24L.