Gas collected over water in Zn and HCl reaction

[jackjones12]

Homework Statement

Given the following chemical reaction:
Zn + HCl ----> ZnCl₂ + H₂(g)

If you measured the total volume of collected gas over water at 20 Celsius to be 428 ml at a total pressure of 845 torr, how many milliliters of 2.6M HCl would be required to produce the correct amount of Hydrogen?

Homework Equations

Dalton's Laws

The Attempt at a Solution

Im not asking for a complete answer here just need help starting, I can't seem to even get how to begin this problem. Any information will be appreciated, thanks.

 

[Borek]

How many moles of gas were collected?

Can you use this number of moles to calculate moles of HCl necessary? Then volume of solution that contains these moles?

 

[jackjones12]

How can i find out how many moles I collected if i wasnt even given how many i started of with. I am sorry to sound dumb but I am having a difficult with this. It might be that I am just missing something really small.

 

[Borek]

You are missing something something really big. It is called ideal gas equation.