How many iron atoms are present in a #16*g# mass of #FeCl_3#?

1 Answer
Mar 25, 2017

Answer:

We work out the molar quantity of iron in a #16*g# mass of #"ferric chloride....."# and get approx. #6xx10^22# individual iron atoms.

Explanation:

#"Moles of"# #FeCl_3# #=# #"Mass"/"Molar mass"#

#=(16*g)/(162.2*g*mol^-1)=0.099*mol#

And so there #0.099*mol# of iron, and #3xx0.099*mol# of chlorine. How does that help us?

Well the mole is simply a number; one mole of stuff SPECIFIES precisely #6.022xx10^23# individual items of stuff.

And here our stuff was #FeCl_3#, and in each mole of this stuff there #3*mol# of chlorine atoms..........BUT one mole of iron.

#"And so number of iron atoms......"#

#=0.099*molxx6.022xx10^23*mol^-1=5.96xx10^22*"iron atoms."#