A piece of potassium metal is added to a sample of zinc chloride. If you started with 3.8 g of potassium and 8.4 g of zinc chloride, determine the limiting reactant, and the amount of metal produced

Explanation:

3.8g              8.4g

2K     +          ZnCl2      =  2 KCl     +     Zn

2 mol             1 mol                                 1 mol

39g/mol        135g/mol

Need 2 mol K for 1 mol ZnCl2

3.8g K/39g/mol = .97 mol K       8.4g ZnCl2/135g/mol  =  0.062 mol ZnCl2

0.062 mol ZnCl2 X 2 mol K/1 mol ZnCl2 =0.124 mol K

ZnCl2 limiting

0.062 mol ZnCl2 = 0.062 mol Zn

0.062 mol Zn x 65 g/mol =   4.0 g Zn