I heated 5,87g of NaHCO3.
My reaction for this is: 2NaHCO3(s) -- Na2CO3(s)+ CO2(g)+H2O(g)
After heating i had 3,48g of Na2CO3(s). but how do i find out how much CO2 (g) and H2O(g) is made?

Question

I heated 5,87g of NaHCO3. 
My reaction for this is: 2NaHCO3(s) -->  Na2CO3(s)+ CO2(g)+H2O(g) 
After heating i had 3,48g of Na2CO3(s). but how do i find out how much CO2 (g) and H2O(g) is made?

whpalmer4 · Answer

You have a balanced equation there, and it says in effect that for every 2 moles of NaHCO3(s) you react, you will make 1 mole each of Na2CO3(s), CO2(g), and H2O(g).

Find the molar mass of NaHCO3, and divide the mass of NaHCO3 by the molar mass to find the number of moles reacted.  Now multiply the number of moles reacted by the ratio of moles of product to reactant (1:2 in all three cases) to find the number of moles of each product.  Finally, multiply the number of moles of each product by the molar mass of each product, and there's your answer.

But wait!

This problem throws you a bit of a curve ball, because you aren't actually reacting ALL of the NaHCO3.  If you figure out how many moles of NaHCO3 you have, and find the mass of that many moles of Na2CO3, you'll discover that the mass is larger than the amount the reaction produced.  That means that you didn't react it all, and some of the NaHCO3 remains. So instead of finding the number of moles by dividing the mass of NaHCO3 by its molar mass, you need to divide the mass of Na2CO3(s) by its molar mass to see how many moles were successfully reacted.  Now multiply the number of moles reacted by the ratio of moles produced (here the ratio is now 1:1 because all 3 products have a coefficient of 1) and then multiply the number of moles of product by the molar mass of each product.