Qualification > Sciences
Need help on CIE Chemistry Paper 5!
ashish:
--- Quote from: moon on October 17, 2010, 12:38:16 pm ---Q3(d)
you have to work out the molecular formula let say your mean value for Cu was 2.00
element mass Ar mole /simplest
O 1.00 16.0 0.0625 1.98 =2
Cu 2.00 63.5 0.0315 1
Copper (I) oxide
CuO2
hmm it is a fictitious value :D just replace yours and do the calculation
How did u get an average 2??? my average is 3.983 so the formula of copper oxide is CuO PLZ help..... thanks in advance
--- End quote ---
ashish:
here is your answer
element mass Ar mole /simplest
O 1.00 16.0 0.0625 1.00
Cu 3.983 63.5 0.0627 1.00
answer: CuO
Deadly_king:
--- Quote from: moon on October 17, 2010, 12:44:36 pm ---what is the volume of water do we have to use???????
Thanx a lot for ur help..
--- End quote ---
This will depend.
Example :
1) First experiment you used 50cm3 of a known concentration of solution.
2) Second experiment you are asked to use 30cm3 of the same solution. Since you need to keep total volume constant(50cm3), add 20cm3 of water ;)
Anytime :)
moon:
--- Quote from: ashish on October 17, 2010, 12:57:10 pm ---here is your answer
element mass Ar mole /simplest
O 1.00 16.0 0.0625 1.00
Cu 3.983 63.5 0.0627 1.00
answer: CuO
--- End quote ---
which value is a fictitious value??? mine or yours
moon:
--- Quote from: Deadly_king on October 17, 2010, 01:09:31 pm ---This will depend.
Example :
1) First experiment you used 50cm3 of a known concentration of solution.
2) Second experiment you are asked to use 30cm3 of the same solution. Since you need to keep total volume constant(50cm3), add 20cm3 of water ;)
Anytime :)
--- End quote ---
did we assume that total volume will be 50cm3 in experiment????
Ur explanation is wonderful. You are doing a great job...thank u very much :)
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