Table salt, NaCl(s), and sugar, C12H22O11(s), are accidentally mixed. A 4.00-g sample is burned, and 3.30 g of CO2(g) is produced. What was the mass percentage of the table salt in the mixture?

Answer 1

Convert 3.30 g CO2 to g C12H22O11. The easy to do that, which isn't taught in schooles these days, is
3.30 x (molar mass C12H22O11/12*molar mass CO2) = about 3.30 x (342/12*44) = about 2 grams but you need to be more accurate than that.
Then mass NaCl = 4.00-about 2 = about 2 g NaCl.
%NaCl = (mass NaCl/mass sample)*100 = ?