posted by Lucy .
Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 48.7 g of sodium are added to water?
2Na + 2H2O ==> 2NaOH + H2
mols Na = grams/molar mass
Using the coefficients in the balanced equation, convert mols Na to mols H2.
Now convert mols H2 to molecules H2. There are 6.02E23 molecules in 1 mol H2. And you have ///// mols H2.
ok thanks for the answer but how do you actually do it?