Stoichiometry Question

Question

Given the following equation: Na2O + H2O ---> 2 NaOH, how many grams of H2Oare in 34.2 grams of NaOH?

Answer 1

I am not sure I understand your question, but are you asking how many grams of H₂O are needed to produce 34.2 g of NaOH?

This equation is already balanced so to solve this problem we first need to know the molar mass of all the products and reactants:

Na₂O: 2*(22.99) + 1*(16.00) = 61.98 g/mol

H₂O: 2*(1.01) + 1*(16.00) = 18.02 g/mol

NaOH: 1*(22.99) + 1*(16.00) + 1*(1.01) = 40.00 g/mol

If we have 34.2 g of NaOH produced, then we can use stoichometry to find out how much H₂O was consumed in the reaction:

(34.2 g NaOH)*(1 mol NaOH/40 g NaOH)*(1 mol H2O/ 2 mol NaOH)*(18.02 g H2O/1 mol H2O) = 7.704 grams of H₂O consumed to produce 34.2 grams of NaOH.

Hope this helps!

-Andrew