Chemistry: Limiting Reactants.?

Question

I need to know how to do this for a quiz tommorow, I know the answer is that Al is the Limiting Reactant but everytime I do it, I come up with HCl being the Limiting Reactant. Can someone show me how to do this?

2Al + 6HCl -----> 2AlCl3 + 3H2
(18g) (75g)

Which is the Limiting Reactant?

Answer 1

Step 1: Find the molar mass of Al and HCl.
Al = 27 g/mol
HCl = 1 + 35.5 = 36.5 g/mol

Step 2: Find the # of moles you have.
Al: 18 g / 27 g/mol = .667 mol
HCl = 75 g / 36.5 g/mol = 2.05 mol

Step 3: Multiply by the coefficients to find the limiting reagent:
Al: .667 mol * 2 = 1.33
HCl = 2.05 * 6 = 12.3