At a pressure of 185 mmHg and a temperature of 55C, what volume would 2.55×1028 molecules of nitrogen gas occupy?

1 Answer
Dec 3, 2014

You will need to use the ideal gas law in order to answer this question. The ideal gas law is represented by the following equation::

PV = nRT, where P is pressure, V is volume, n is number of moles, R is the gas constant, and T is temperature in Kelvins.

First there are two conversions that must be made. The temperature in degrees Celsius needs to be converted to Kelvins. This is done by adding 273 to the Celsius temperature:
55.0oC+273=328K

The number of molecules of nitrogen gas must be converted to moles of nitrogen gas. 1 mol N2molecules=6.022 x 1023molecules N2.

2.55 x 1028molecules N2 x 1mol/6.022 x 1023 = 42345 mol N2

Now we're ready to solve the problem.

Given/Known:
P = 185 mmHg
n = 42345 mol N2
R = 62.36367 L mmHg K1mol1
T = 328K

Unknown:
V

Equation:
PV = nRT

Solution : Rearrange the equation to isolate V by dividing both sides by P.

V = nRTP = (42345mol)(62.36367L mmHg K1mol1)(328K)÷185 mmHg

V = 4.68 x 106L (rounded to three significant figures)