Limiting reactant worksheet
1. consider the following reaction: 2 ai + 5 hbr
2 aibt,
3 h,
a. when 3.22 moles of al reacts with 4.96 moles of hbr, how many moles of h, are formed?
b. what is the limiting reactant?
c. what is the excess reactant?

a) 1.61 mol

b) Al is limiting reactant

c) HBr is in excess

Explanation:

Given data:

Moles of Al = 3.22 mol

Moles of HBr = 4.96 mol

Moles of H₂ formed = ?

What is limiting reactant =

What is excess reactant = ?

Solution:

Chemical equation:

2Al  + 2HBr  → 2AlBr + H₂

Now we will compare the moles:

                Al              :               H₂

                  2              :               1

                 3.22         :            1/2×3.22 = 1.61 mol

                HBr            :              H₂

                 2                :               1

                4.96            :          1/2×4.96 = 2.48 mol      

The number of moles of H₂ produced by Al are less it will be limiting reactant while HBr is present in excess.

Moles of H₂ :

Number of moles of H₂ = 1.61 mol