A #1.85*g# mass of calcium chloride was obtained from a #1.23*g# mass of #"calcium oxide"# and excess hydrochloric acid. What was the percentage yield?

1 Answer
May 6, 2017

Answer:

We need #(i)# a stoichiometric equation...........and get a yield of #77%#.

Explanation:

#CaO(s) +2HCl(aq) rarr CaCl_2(aq) + H_2O(l)#

And #(ii)# equivalent quantities of #"calcium oxide"# and #"calcium chloride"#.

#"Yield"# #=# #"Moles of calcium chloride"/"Moles of calcium oxide"xx100%#

#=((1.85*g)/(110.98*g*mol^-1))/((1.23*g)/(56.8*g*mol^-1))xx100%=77%#

Sometimes when you do these equations, you might get a situation where the stoichiometry is NOT 1:1, and the yields must be appropriately calculated. This is why teachers insist that chemical reactions be stoichiometrically balanced.