lithium metal reacts with water to give lithium hydrogen gas. if 275 mL of hydrogen gas is produced at STP, wh

Question

lithium metal reacts with water to give lithium hydrogen gas. if 275 mL of hydrogen gas is produced at STP, what is the mass of lithium that reacted?

Answer 1

Li + H2O -> LiO + H2

275 ml H2/22.4 L/mol = 1.23E-2 mol H2

1.23E-2 mol Li * 6.94 g/mol = 0.0852 g Li (to 3 sig figs)