Question

A storage tank at STP contains 27.3 kg of nitrogen (N2). A) What is the volume of the tank? B)What is the pressure if an additional 28.8 kg of nitrogen is added without changing the temperature?

Answer 1

Using Ideal gas law:

PV = nRT

Part 1: find the volume of tank

V = nRT/P

n = number of moles of N2 = m/Mw = 27.3 kg/(28*10^-3 kg/mol) = 975 moles

R = gas constant = 8.314

T = 0 C = 273 K

P = 1 atm = 1.01325*10^5 Pa, So

V = 975*8.314*273/(1.01325*10^5) = 21.84 m^3

Part B.

Since temperature is constant, So

Now when 28.8 kg Nitrogen is added, then new number of moles will be:

n1 = m1/Mw = (27.3 + 28.8)/(28*10^-3) = 2003.57 moles

V1 = V, and T1 = T, So

P1 = n1*R*T1/V1

P1 = 2003.57*8.314*273/(21.84)

P1 = 208221.01 Pa = 2.08*10^5 Pa

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