Im having trouble with this question. A sample of NaBr contains 22.34% Na by mass. considering the law of constant composition how many grams of sodium does 8.01 grams sample of sodium bromide contain?

##1.79## ##g##

I'm assuming you mean how many grams of sodium does ##8.01## grams of sodium bromide have, because Bromine would not have any sodium in it.

If ##NaBr## is 22.34% sodium, then the amount of Sodium in a sample would be ##(22.34/100)## x ##("amount of NaBr")##.

Therefore the amount of sodium in ##8.01## grams of ##NaBr## is ##(22.34/100)##x ##(8.01## ##"grams")## = ##0.2234## x ##8.01## = ##1.79## ##g## of Sodium.