Given the following reaction:
Zn + CuCl2 —> ZnCl2 + Cu

How many moles of ZnCl2 will be produced from 23.0g of Zn, assuming CuCl2 is available in excess?

The answer to your question is 0.35 moles of ZnCl₂

Explanation:

Data

moles of ZnCl₂ = ?

mass of Zn = 23 g

mass of CuCl₂ = excess

Balanced chemical reaction

             Zn + CuCl₂   ⇒   ZnCl₂  +  Cu

Process

1.- Convert the mass of Zn to moles

-Look for the atomic mass of Zn

Atomic mass = 65.4 g

-Convert the grams to moles

            65.4 g 1 mol

             23 g    x

               x = (23 x 1)/65.4

               x = 23 / 65.4

               x = 0.35 moles of Zn

2.- Calculate the moles of ZnCl₂ using proportions and cross multiplication, and the coefficients of the balanced chemical reaction.

              1 mol of Zn 1 mol of ZnCl₂

             0.35 moles of Zn  x

              x = (0.35 x 1) / 1

              x = 0.35 moles of ZnCl₂

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.