00:01
Okay, so we're told that we have 9 .21 grams with a mass of a substance contained in a volume of 5 liters at a pressure of 725 .0 millimeters of mercury and at a temperature of 22 .5 degrees, we need to find the molar mass of the gas.
00:19
To do that, we're going to use the ideal gas law, which is pv equals n over t.
00:25
And we're going to solve that for moles, which is n.
00:27
So dividing both sides by rt, we get n is equal to pv over rt.
00:33
And when we use the ideal gas law, temperature has to be in kelvin.
00:38
So i added 273 to the temperature in celsius to use the value in kelvin.
00:45
And the value of r here is not going to be 0 .0821 because we're dealing with millimeters of mercury.
00:52
And there's 760 millimeters of mercury in an atmosphere.
00:55
So when we take the normal gas constant, multiply it by 760, this is the value we get...