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!

3 answers

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