How many molecules of hydrogen are produced if 13.05 g of Zn reacts with excess hydrochloric acid equation Zn plus HCL equals ZnCl2 plus H2?

Answer 1

This is a stoichiometry problem. First you have to balance your reaction:

Zn + 2HCL = H2 + ZnCl2
(This is irrelevant to answering the question because Zn and H2 both have coefficients of 1, but it's good to know)

So you're given 13.05g of Zinc, you have to convert that to moles first in order to find moles of hydrogen, then molecules of hydrogen.

13.05g Zn * 1molZn/65g = .201mols Zn

To convert mols Zn to mols H, use the ratio 1 mol H2 to 1 mol...so you have .201 mols of H2

Now that you've got .201 mols of H2, you can find the molecules of H2. Use Avogadro's Number:

.201mols H2 * 6.02x10^23molecules/1mol

...and there's your answer!

Answer 2

thanks!