How many chlorine atoms are contained in a #2*mol# quantity of #FeCl_3#?

2 Answers
Aug 18, 2017

#3.6*10^24# Chlorine atoms.

Explanation:

Each #FeCl_3# has three Chlorines.
Here, we can use a conversion factor.
#(3Cl#/molecule)#*(6.022*10^23# molecules#/mol)*(2.0mol)#
Molecules and molecules cancel out. Moles and moles cancel out.
We are left with:
#3Cl*6.022*10^23*2.0#
Simplifying and giving the answer to 2 significant figures, we get:
#3.6*10^24# Chlorine atoms.

#6xxN_A# chlorine atoms, where #N_A=6.022xx10^23#

Explanation:

If you were asked how many chlorine atoms there were in #"1 dozen"# #FeCl_3# formula units, I think you would very quickly answer that there were #"3 dozen"#, i.e. #36# chlorine atoms.

Here you were asked the SAME QUESTION using the mole, #N_A=6.022xx10^23*mol^-1# as your counting unit.

And thus there are ................

#2*molxx3*"chlorine atoms/formula unit"xx6.022xx10^23*mol^-1#

#=??*"chlorine atoms"#.