Question

how many grams of sodium are needed to produce 33.2L of hydrogen gas according to the following reaction at 25 degrees celcius and 1 atm?

Sodium(s) + water(l) yields to sodium hydroxide (aq) + hydrogen (g)

Answer 1

1) find the moles of H2 produced

Given:

P = 1.0 atm

V = 33.2 L

T = 25.0 oC

= (25.0+273) K

= 298 K

find number of moles using:

P * V = n*R*T

1 atm * 33.2 L = n * 0.08206 atm.L/mol.K * 298 K

n = 1.357 mol

2)

the balanced chemical reaction is:

2 Na (s) + 2 H2O (l) —> 2 NaOH (aq) + H2 (g)

from reaction,

moles of Na required = 2*moles of H2 produced

= 2*1.357 moles

= 2.714 moles

Molar mass of Na = 22.99 g/mol

mass of Na,

m = number of mol * molar mass

= 2.714 mol * 22.99 g/mol

= 62.4 g

Answer: 62.4 g