1. The problem statement, all variables and given/known data Its the end of the year in my AP chemistry class and one section of our lab final includes finding the molar mass of an unknown gas. we are given a balloon filled with the gas and we must conduct any tests to figure the molar mass out 2. Relevant equations pv=nrt i believe the equation relating density and molecular weight is MW=drt/p d=m/v 3. The attempt at a solution heres what i've thought of measure the weight of the filled balloon (our scales go up to 2 or 3 decimals) fill a graduated cylinder with water, flip it upside down in a bucket of water and release the gas into the graduated cylinder to get the volume then dry the balloon and get the weight again use d=m/v to get the density and then use the above equation to calculate the MW however i have some problems with this strategy will the presence of gas effect the mass of the balloon (noting the sig figs of the scale) what temperature do i use for mw=drt/p, the temp of the water or room temp? if you have a diff strategy or any suggestions PLEASE let me know thanks!