letters Consewation of Matter To the Editor:
I found the second demonstration on the Conservation of Matter described by Martin, et al. in Tested Demonstrations [J. Chem. Educ. 1992, 69, 9251 so irresistible, I had to try it for myself. I discovered in the process that it has a auantitative asvect that allows measurement of the moIrculer weight of'rnrbon dloxlde. l uwd ;I 250-rnl. \wlum(,tr i c flask contninin~nhoutI N 1 ml. ofwater,. weiahvd to 0.01 g on a top-loading balance, and a s my source of gas, I used two Alka Seltzer tablets. They are conveniently smashed with a brick while still i n
