Assume that 5.00 grams of zinc react with excess HCl according to the following equation:

Question

Zn + 2HCl = ZnCl2 + H2
The hydrogen was collected over water at 20.0C and the prssure of the atmosphere is 751 mmHg. The pressure of the water vapor at 20C is 17.5 mmHg. How many moles of hydrogen gas should be produced? Determine the theoretical volume in liters of the H2 collected.

Answer 1

moles H2=molesZn=5/30=1/6

PV=nRT
V=nR(273+20)/(751-17.5)
n is 1/6, R is in units of liters*mmHg/K

verify you have the correct gas constant in those units.