# A Chem Math Problem

• Jun 3rd 2008, 01:33 PM
mike_302
A Chem Math Problem
I did the work and all... and maybe I shouldn't even be posting this here, but I need the answer tonight, and this has a fair amount of math in it so I thought I could try here... The basis of the question is chemistry, but I guess the main question is if the math was all done right.

http://i160.photobucket.com/albums/t..._302/HW001.jpg
• Jun 3rd 2008, 02:27 PM
o_O
I'm guessing you're asked to find the amount of sodium carbonate to evolve a specific amount of gas that meet the given conditions. The idea in solving for it seems good.

The only problem I can see is that when applying the ideal gas law, the gas constant has a value of $\displaystyle 8.314 \text{ kPa L mol }^{-1} \text{K}^{-1}$. Notice the pressure units are in kilo-Pascals not in torr. I don't know whether or not your class takes this into consideration but I'd say the conversion is necessary as I don't think 1 kPa = 1 torr.
• Jun 3rd 2008, 02:32 PM
mike_302
Ahh, I see exactly what you mean, and in reviewing while waiting for a reply, I figured out that I need to use kPa in the PV=nRT equation... Thank you for pointing that out. When I first did this question I was thinking about the combined gas law where any form of pressure unit can be used.

Thakns again!