posted by John .
what is the percent by mass of NaCHO3 in a solution containing 12g NaCHO3, dissolved in 450mL of water?
Density of H2O= 1g/mL, solve for mass in g
400ml*(1g/mL)= mass of H2O
[12 g of NaCHO3/(mass of H2O + mass of NaCHO3)]*100= % mass of NaCHO3