Author Topic: Organic chem question (Read 614 times) Tweet Share

loz.xoxo · « **on:** April 06, 2013, 01:20:42 pm »

Hey guys!
Organic chemistry question here:

A mixture contains several different organic liquids all of which boil at temperatures greater than 50^oC. The compounds present in the mixture are separated. Compound X is analysed as follows.

Compound X is vapourised. At a temperature of 120^oC and a pressure of 115 kPa, a 0.376g sample of the vapour occupies 124mL.
a) Calculate the molar mass, in gmolL-1, of compound X.

Any takers?? All my calculations look wrong when I do them... Haha

Mr. Study · « **Reply #1 on:** April 06, 2013, 01:36:11 pm »

My chem might be rusty but here goes.

$ \begin{align} pV&=nRT \\ n&=\frac{pV}{RT} \\ &=\frac{115 \times 0.124}{8.31 \times (120+273)} \\ &= 0.00436642446 \\ n&=\frac{m}{M} \\ M(Molar Mass)&= \frac{m}{n} \\ &=\frac{0.376}{0.00436642446} \\ &= 86.1116 \\ \end{align} $

But our lowest sig. figs was to 3 decimal places, so 86.1

EDIT: Sorry for the Latex ... I have no idea what is wrong . Oh and I wasn't too good with sig. figs ... so ... >_<

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Author Topic: Organic chem question (Read 614 times) Tweet Share

loz.xoxo

Organic chem question

Mr. Study

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