Question

solid sodium reacts violently with water producing heat, hydrogen gas and sodium hydroxide. How many molecules of hydrogen gas are produced when 65.4g of sodium are added to water? 2Na(s)+ 2H2O(l) -->. 2NaOH(aq) + H2(g)

Answer 1

Molar mass of sodium=23g
2 mole sodium gives 2 g H2
i.e 46g sodium gives 2g H2
so 65.4g will give=2.84g H2
now no. of molecules = 2.8/2*avogadros number