URGENT HELP NEEDED CHEMISTRY

[bamteck]

0.080 g of a liquid compound was completely vaporised in a gas syringe at 127 'C and a pressure of 1 atmosphere. 81cm3 of vapour was produced.

(i) Calculate the relative molecular mass of the liquid.

(ii) The liquid used was pure methanol. Suggest reasons why there is a difference between the theoretical value and the value obtained in (d)(i)

 

[hassam]

for 1st part find no. of moles using PV=nRT.......THEN equate n=.08/Mr......from here find Mr
2nd question seems a bit awkward.....wud be helpful if u could add litlle bit detail from the context

 

[dreamiscollapsing]

hassam is right about the first part.

As for the second, I am pretty sure that the answer is something like this.
some of the mass of the methanol is lost due to evaporation while getting it into the gas syringe. As the mass used in the calculation is greater than the "true" value, the Mr calculated is also greater.