Question

Sulfuric acid dissolves aluminum metal according to the following reaction:

2Al(s)+3H2SO4(aq)--->Al2(SO4)3(aq)+3H2(g)

Suppose you wanted to dissolve an aluminum block with a mass of 14.2 g.

A) What minimum mass of H2SO4 would you need?

B) What mass of H2 gas would be produced by the complete reaction of the aluminum block?

Answer 1

balance chemical reaction

2Al(s) + 3H2SO4(aq) ---> Al2(SO4)3(aq) + 3H2(g)

2 mole of Al react with 3 mole of H2SO4 and produce 1 mole of Al2(SO4)3 and 3 mole of H2 gas

a) find moles of Al in 14.2 g block

no. of moles = given mass / molar mass { molar mass Al = 26.98 ~ 27 g/mol}

no. of moles = (14.2 g / 26.98 g/mol) =0.526 moles

2 mole Al need 3 mole of H2SO4

so 0.526 moles of Al need = ?

H2SO4 = 0.526(3/2) = 0.789 moles ~ 0.79 moles

mass of H2SO4 = 0.79 moles x 98.08 g/mol = ~ 77.48 g

B) 2 moles of Al produce 3 moles of H2 gas

moles of H2 gas = 0.79 moles

mass of H2 g = 2g/mol x 0.79 moles = 1.58 g