Given initial mass, determine expected mass of potential products.

[beefjerky]

Ok so I have two chemical equations for two possible decomposition reactions.
2NaHCO = H2O + CO2 + Na2CO3
2NaHCO3 = H2O + 2CO2 + Na2O

I already have the initial masses of both of them, .493g.  I need to find out the expected mass of each of the products.  Then I need to use the expected mass of each of the products and the measured product mass(I already have) to determine which reaction naturally occurred.

Any ideas?

[kingchemist]

H2O and CO2 will not be part of the products because the water will become stream and CO2 is a gas. So the masses measured will be Na2CO3 or Na2O.
Find the formula masses of NaHCO3, Na2CO3 and Na2O and then express these as mole masses (or gram formula mass) (eg if FM=100, GFM (1 mol) = 100g)
Then refer to the equations and calculate the expected mass of solid product.
2 mol NaHCO3 --->1 mol Na2CO3
      gfm         --->         gfm
  so 0.493g     --->       ?

Repeat this for the other reaction and compare with expermental results.
Hope this helps ( and just from knowledge I expect the first reaction to be more likely)