Question

A closed vessel having capacity 200ml is filled with hydrogen gas at STP . Calculate 1) number of moles of hydrogen gas filled in the vessel 2) pressure of hydrogen gas in the vessel at 273 °C 3) root mean square velocity of hydrogen gas at STP 4) The value of Cpand Cv for hydrogen gas

Answer 1

just use PV = nRT in the first 2 parts .

a)n = PV/RT
R = 8.314
V = 0.2 L = 0.2*10^-3 m³
P = 10^5 Pa
T = 273K

b) p = nRT/V
from the above data we see that pressure equals atmospheric pressure (pressure at STP = 1atm)
ie 10^5 pa

c) V rms = √3RT/M° = √(3*8.3*273 / 2*10^(-3))

d) Cv = 5/2 R for diatomic gas

Cp = Cv + R = 7/2 R