00:01
For this exercise, we have to know the ideal gas equation, which is the pressure of the gas times its volume has to be equal to the number of moles of the gas, times the universal gas constant, times the temperature of the gas.
00:15
So for this exercise, we have to use this equation in order to calculate the number of moles of a gas that is at an atmospheric pressure, so 101 kilo -pascal, that has also a temperature of 20 degrees celsius, which in the degree kelvin is 293, and has a volume of one cubic meter.
00:49
So we just substitute this in the ideal gas equation.
00:53
Hav .m.
00:54
It's going to be pv divided by rt, so 101 kilo -pascal times one cubic meter divided by the universal gas constant, so 8 .314 joules per mole times kelvin times the temperature, so 293 kelvin.
01:26
This is going to be equal to 41 .6 moles.
01:38
Now, question b, so question b, that the avogrados number of molecules has a mass of 28 .9 grams.
01:52
So basically, this means that 6 .02 times 10 to the 23 molecules of this gas, weight, 28 .9 times 10 to the minus 3 kilograms.
02:18
And the exercise ex -cos to use this information and the information of the answer of question a in order to calculate the mass of 1 cubic meter of air and compare the mass of 1 cubic meter of air with the tabulated density of air.
02:41
So we are going to calculate the density...