Question

how many molecules are there in 10 litre of gas at a pressure of 75 cm at 27 ° C???

Answer 1

Well, by using the ideal gas equation “PV = nRT” we have the pressure, volume and the temperature from the information you’ve given and we can find ’n’, the number of moles.

First things first, all values should be in SI units

10L = 0.01metres

75cmHg = 99991.79Pa to the nearest hundredth

27C = 300K

Now making n the subject, we have :- n = PV/RT, substituting values, we have n=0.4mols.

Now you multiply the number of moles with the Avagardo constant which is 6.02 x 10^23 and your answer shall be 2.408 x 10^23