Question

How many moles, kilograms, and molecules of air are present in an automobile tire when it is at a pressure of 30 psig, and at 30 C? Volume of tire is 100 liters.

Answer 1

we know the Ideal Gas Equation,

PV = nRT (n is number of moles here)

from question,

P = 30 psig = 206842.718 pascal

T = 30 °C = 303 K

V = 100 liters = 0.1

and Gas Constant R = 8.314 J / mol. K

now from formula,

n =

n = ?

n = 8.21 MOLES

NOW, we know that

n = =

or , m = n * M

m = 8.21 * 28 (here i took the molar mass of Nitrogen)

m = 229.9 gm = 0.2299 kg

And for number of molecules(N),

N = n * N_A (here is N_A is Avagrado number)

N = 8.21 * 6.022×10²³

N = 4.944 ×10²⁴ molecules present in tire.