How many molecules of ethane gas, #C_2H_6#, are in 33.6 L at STP?

1 Answer
Aug 17, 2016

Answer:

Well, one mole of ideal gas at #"STP"# occupies #22.4*L#.

Explanation:

So, assuming ethane behaves ideally, #33.6*L# of the stuff represents #(33.6*L)/(22.4*L*mol^-1)# #=# #1.5*mol#.

Now, it is a fact that #1# #mol# of any substance contains #"Avogadro's Number, "N_A# of particles, i.e. #6.022xx10^23# particles.

And thus #"number of ethane gas molecules "=6.022xx10^23*cancel(mol^-1)xx1.5*cancel(mol)# #~=# #9xx10^23# #"ethane formula units"#.