Question

When zinc metal is reacted with hydrochloric acid, zinc chloride and hydrogen gas are produced. If 16.4 ml of 2.14 M HCl are used:

a) how many grams of zinc metal are needed to completely use up the acid?

b) What will be the molarity of the aqueous product?

Please show all work. Thank you!

Answer 1

I wont show all work, ever. What teacher would ever do that?

balance the equation
Zn+ 2HCl>>ZnCl2 (aq) + H2(g)
so for each mole of acid, you need half that moles of Zn.

moles HCL: Volume*concentraioninMolarity
moles of Zn needed: half of that.
grams of Zn: molesZn*atomicmassZn
Molarity of product? it is a solution of ZincChloride: figure the moles of ZnCl2 made (same moles as Zn), then
molarityZnCl2= molesZnCl2/volume
where volume is still .0164 liters.

Answer 2

This is a regular stoichiometry problem.
Zn + 2HCl ==> ZnCl2 + H2

1. Convert HCl to moles. moles = M x L = ?
2. Use the coefficients in the balanced equation to convert moles HCl to moles Zn.
3. Convert moles Zn to grams. g = moles to molar mass.

b) Convert moles (either Zn or HCl) to moles ZnCl2. Then M = moles/L.

Answer 3

Thank you both for your help! You made it very clear