chemistry
posted by Blain .
for this question
How many liters of H2 gas at STP are produced
when Zn reacts with 125 mL of 6.00 M HCl?
my book answers it this way:
0.125 L x 6.00 mole HCl x 1 mole H2 x 22.4 L
1 L 2 mole HCl 1 mole
= 8.40 L of H2 gas
where did the 22.4L come from?

at STP (standard temperature and pressure: T = 0 deg C , P = 1 atm), one mole of gas occupies a volume 22.4 L . or to you can derive this one using ideal gas law:
PV = nRT
where
P = 1 atm (STP)
T = 273.15 K (STP)
R = gas constant = 0.0821 L*atm/molK
n = 1 mol
hope this helps~ :)