If you have 84.1 grams of Zinc how many grams of ZnCl2 will form?

Question

Zn + 2 HCl  →  ZnCl2  + H2

 

 

If you have 84.1 grams of Zinc how many grams of ZnCl2 will form?

Answer 1

Hello Kelli,

Lets start with what we know:

Zn + 2 HCl  →  ZnCl2  + H2

84.1 g Zn We have grams of Zn how do we get to grams of ZnCl2?

We need to change grams of Zn to moles of Zn, then moles of Zn to moles of ZnCl2, then to grams of ZnCl2.

So first how do we go from grams of something to moles of something? We use the molar mass (from periodic table)

84.1g Zn * 1 mol Zn/ 65.38g Zn = 1.2863 mol Zn

So we have moles of Zn. How do we get from moles of Zn to moles of ZnCl2? We use the balanced equation!!

1 mole of Zn = 1 mole of ZnCl2 (the coefficients in the balanced equation)

So,

1.2863 mol Zn * 1 mol ZnCl2 / 1 mol Zn = 1.2863 mol ZnCl2

Now how do we get from moles ZnCl2 to grams of ZnCl2? We use the molar mass of ZnCl2!

1.2863 mol ZnCl2 * 136.272 g ZnCl2 / 1 mol ZnCl2 = 175.29 grams of ZnCl2