posted by Anonymous .
In chemistry we are doing a lab that involves crucibles and Mg ribbon, we have three days to complete the lab.
Anyways do you think it would be alright to substitute the mass of the crucible we had the first day with the mass of the crucible we had today? We know how much the Mg ribbon weighed so it shouldn't effect the rest of the data, my partner said that we should just use the one mass of the crucible for the first part of the lab and the mass of the second crucible for the other part of the lab-makes no sense to me.
I won't be much help. It may make a difference but it all depends upon what the instructor will be checking and how much work you completed the first day vs the next two days. If you heated the Mg ribbon and crucible the first day but continued heating the second day it will make a difference if you substitute different masses for the crucible and what your partner thinks probably is the way to go. If however, you know the mass of the Mg AND THE MASS of the oxide, it makes little difference what you do for those are the two masses that are important.
thanks, I'll ask my teacher just to make sure. :)