Question

Sulfuric acid can dissolve 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 30.0 g

1-What minimum amount of H2SO4 in grams would you need? 2-How many grams of H2 gas would be produced by the complete reaction of the aluminum block?

Answer 1

From the stoichiometric equation

1)

2 moles of Al (2molx 27g/mol) requires 3 moles of H2SO4 ( 3mol x 98g/mol)

If 30g of Al is used mass of H2SO4 needed = [ 30gAl x ( 3mol x 98g/mol) H2SO4 ] / (2molx 27g/mol) Al

= 163.33 g of H2SO4

2) From the equation

2 moles of (2molx 27g/mol) gives 3 moles of H2 (3molx 2 g/mol)

if 30g of Al is used mass of H2 given out = 30g Al x 3 molx 2g/mol H2 / 2mol x 27g/mol Al

= 3.33 g of H2