Chapter 3 - Chemical Reactions and Reaction Stoichiometry - Exercises - Page 116: 3.61c

0.61 grams

For each mole of Na2SiO3, you need 8 moles of HF. Therefore, if we have 0.800g of HF then we need to convert this to moles. H is 1 g/mol F is 19 g/mol 20 g/mol. Then we have 0.8g * (1 mole/20g) = 0.04 moles HF We need 8 moles HF for every mole of Na2SiO3 so 0.04/8 = 0.005 moles Na2SiO3. The molar mass of Na2SiO3 is: Na is 23, 23*2 = 46 Si is 28 O is 16, 3*16 = 48 46+28+48 = 122 g/mol 0.005 moles * 122g/mol = 0.61 grams