DR.BOB HELP CHEMISTRY!
posted by Rara on .
How many milliliters of a 0.3 molar HCl
solution are needed to react completely with
8 grams of zinc according to the following
equation?
? HCl + ? Zn → ? ZnCl2 + ? H2
Answer in units of mL

First, you need to balance the equation. Can you do that?
You will need two moles of HCl per mole of zinc.
Ask yourself this question:
How many moles of zinc is 8 grams? 
I balanced it and got:
2HCL + Zn > ZnCl2 + H2
And then to find moles I did: 8/65.37 and got 0.1124 moles.
But now I'm stuck, what do I do next? 
You are doing fine so far.
You need 2*0.1124 = 0.2248 moles of HCl.
One liter of the solution contains 0.3 moles of HCl.
You need a bit less than a liter of the acid solution. 
Okay, so would I divide 0.3 by 0.2248? >_> I'm sorry, my chemistry is my weakest subject. :(

No, you need less than a liter.