Re: A Hard Chem. Problem! Please help!!!

farooq_w_at_hotmail.com
Date: 10/25/04 

Date: 24 Oct 2004 21:47:26 -0700

XxVanillaSwirlyxX wrote:
> A compound of Ca, C, N, and S was subjected to quantitative analysis
> and molar mass determination, and the following data was obtained. A
> .250 g sample was mixed with Na2CO3 to convert all of the Ca to .160
> g of CaCO3. A 0.115 g sample of the compound was carried through a
> series of reactions untill all of its S was change to .344 g of
> BaSO4. A 0.712 g sample was processed to liberate all of its N as
> NH3, and .155 g NH3 was obtained. The molar mass was found to be
> approximately 156 g. Determine the empirical and molecular formulas
> for this compound.

Ignore the given reactions and just focus on the weights of CaCO3,
BaSO4 and NH3. Calculate the number of moles each element in the sample
eg.
1 mol CaCO3 = 1 mol Ca = 1 mol C
1 mol BaSO4 = 1 mol S
1 mol NH3 = ?? mol N
and find the number the number of moles of Ca, C, S and N in 100 grams
arithmetically in the sample and study a solved example from your book.