Question

When aluminum is placed in concentrated hydrochloric acid, hydrogen gas is produced.

2Al(s) + 6HCl(aq) ---- 2AlCl3 (aq) + 3H2 (g)

What volume of H2(g) is produced when 2.00 g of Al(s) reacts at STP?

Answer 1

Molar mass of Al = 26.98 g/mol

mass of Al = 2 g

mol of Al = (mass)/(molar mass)

= 2/26.98

= 0.0741 mol

we have the Balanced chemical equation as:

2Al(s) + 6HCl(aq) ---- 2AlCl3 (aq) + 3H2 (g)

From balanced chemical reaction, we see that

when 2 mol of Al reacts, 3 mol of H2 is formed

mol of H2 formed = (3/2)* moles of Al

= (3/2)*0.0741

= 0.1112 mol

we have:

P = 1.0 atm

n = 0.1112 mol

T = 273.0 K

we have below equation to be used:

P * V = n*R*T

1 atm * V = 0.1112 mol* 0.08206 atm.L/mol.K * 273 K

V = 2.49 L

Answer: 2.49 L