M.HNO3 = 1+14+3x16 = 63 g/mol
M.NaNO3 = 23+14+3x16 = 85 g/mol
2 moli md g m g
Na2CO3 + 2HNO3 --> 2NaNO3 + H2O + CO2
1 2x63 2x85
=> md = 2x2x63/1 = 252 g HNO3
c% = mdx100/ms
=> ms = mdx100/c% = 252x100/60
= 420 g sol. HNO3
=> m = 2x2x85/1 = 340 g NaNO3