[chawin]

hi everyone

i am a junior college student currently having a chemistry project which will be counted in our exam grades, and i encountered some problems while finding information for my project. i hope that the undergraduates here might be able to help me out!

firstly, i would like to know whats gravimetric analysis by gas and whats gravimetric analysis by reaction with acids.
i tried googling out but to no avail. the local library isnt of much help either.

If so, then which method is more accurate?

just for your information, we are required to determine the percentage purity of a sample of calcium carbonate.



thanks to all those who replied 
 
 
 

[JGK]

http://en.wikipedia.org/wiki/Gravimetric_analysis

[khaly]

hii,

All you need are a couple of common chemicals to turn your normal copper-colored pennies (or other mainly-copper object) from copper to silver and then to gold. No, the coins won't really be silver or gold. The actual metal involved is zinc. This project is easy to do. While I don't recommend it for very young kids, I'd consider it appropriate for kids ages third grade and older, with adult supervision.