Metal hydrides react with watt to form hydrogen Strontium hy

Metal hydrides react with watt, to form hydrogen Strontium hydride reacts according to the equation. SrH_2(s) + 2H_2O (l) rightarrow Sr(OH)_2 (s) + 2H_2(g) 5.63 g of SrH_2 are added to 3.63 g of H_2O. The reaction occurs immediately. calculate the mass of hydrogen produced when this reaction occurs. The hydrogen gas is collected by displacement of water. What volume of hydrogen gas would be collected if the total pressure in collection container, after the reaction has gone to completion, is 754 mmHg and the temperature of the gas is 25.0 degree C. Complete the following table.

Solution

4. For the reaction,

SrH2 + 2H2O --> Sr(OH)2 + 2H2

a) moles of SrH2 = 5.63 g/89.636 g/mol = 0.063 mol

moles of H2O = 3.63 g/18 g/mol = 0.2017 mol

If all of SrH2 has reacted, we would need = 0.063 x 2 = 0.126 mols of H2

since moles of H2 available is greater than required amount, SrH2 is the limiting reactant

moles of H2 formed = 2 x 0.063 = 0.126 mol

mass of H2 formed = 0.126 x 2.01 = 0.253 g

b) Volume of H2 collected = nRT/P

                                          = 0.126 x 0.08206 x 298/(745/760)

                                          = 3.143 L