chem lab help?

Question

HI i did a lab on finding the molar mass of CO2. It involves subliming dry ice in a flask and using the ideal gas law to find MM. IN this lab we were suppose to find the volume using flask, water and graduated cylinder, the thing is I wasn't quite sure how my group did this and I don't ahve any of their number so I can't answer the question. Do any of you have any idea how to do this?

This is the link to the lab, the question i need help on is in the Analysis and questions area. The info is #4 in the procedure!
http://facweb.northseattle.edu/byool/CO2...

Thanks for all your help!

the real link:
http://facweb.northseattle.edu/byool/CO2.pdf

Answer 1

I couldn't get to the listed site but;

There are several variations, but, usualy, these experiments for molar mass of a vapor involve determining the mass, volume, temperature and pressure of the vapor, then setting up the ideal gas law to solve for moles.

PV=nRT ---> n = PV/RT

Once you find n and you know the weight of the contained vapor, you can easily get molar mass of the vapor.

Usually, the volume of the container is measured from the weight of contained water, or by measuring the volume of contained water.

Do you mean you don't have their phone #'s or you don't have their data #'s? Without the data, there isn't any way to know the answer, can't you E-mail one of them and get the data?

Added: (the new link works)

From the lab instructions; it looks like you were supposed to fill the erlenmeyer with water, then put the stopper in with the same degree of firmness as when stoppering the CO2 gas;(some water will be forced out) This volume of water should match the volume of space the CO2 occupied. Then you pour out the water into the graduated cylinder and measure the volume. I hope this is of help.

Answer 2

The link did not work. Call someone in your class (preferably in your group) and inquire.