Question

Sodium hydride racts with excess water to produce

aqueoussodium hydroxide and hydrogen gas. What mass (in grams) of
sodiumhydride will produce 982 mL of gas at 28.0 C and 765 torr,
when thehydrogen fas is collected above water? The vapor pressure
of waterat this experiment is 28 torr.

Answer 1

0.96g of sodium hydride

Step-by-step explanation:

Equation of reaction:

NaH + H20 = NaOH + H2

Mass of hydrogen gas produced (m) = PVM/RT

P = 765torr - 28torr = 737torr = 737/760 = 0.97atm, V = 982mL = 982cm^3, M = 2g/mol, R = 82.057cm^3.atm/gmol.K, T = 28°C = 28 + 273K = 301K

m = (0.97×982×2)/(82.057×301) = 0.08g of hydrogen gas

From the equation of reaction

1 mole (24g) of sodium hydride produced 1 mole (2g) of hydrogen gas

0.08g of hydrogen gas would be produced by (24×0.08)/2 = 0.96g of sodium hydride