Question

What mass of hydrogen is produced when 0.400 moles of water react completely in the following equation? 2Na + 2H₂O

Answer 1

Looking at the chemical equation we see that,

2 moles of H2O gives 1 mole of H2

therefore, 0.400 moles of H2O will give = 1 x 0.400 / 2

                                                               = 0.200 moles of H2

Molar mass of H2 = 2.02 g/mol

Thus the mass of H2 produced would be = moles of H2 x molar mass of H2

                                                                  = 0.200 x 2.02

                                                                  = 0.404 g of H2 will be produced

Therefore the correct answer would be, mass of hydrogen produced when 0.400 moles of water react completely in the following equation: 2Na + 2H₂O