Start with the 19.7 mol HNO3. use dimensional analysis to correctly convert from mol HNO3 to gram H2O. so, it should look similar to 19.7 mol HNO3 x (2 mol H2O/6 mol HNO3) x (18 g H2O/1 mol H2O)
the first parenthesis’ numbers were received from the balanced equation (for every 6 mol HNO3, 2 mol H2O formed). the second is converting from moles to grams by using the molar mass of H2O (1+1+16). you should get 709.2/6. once you divide those, the answer should be 118.2 g H2O. I’m not sure if your computer requires you to use the exact answer or stop at the correct number of significant digits, but if it does then it might just be 118. g H2O.
