Question #2694b

1 Answer
Jun 17, 2017

Answer:

The formula mass is 399.86 u.

Explanation:

The calculation might be easier if you first multiply all atoms inside the parentheses by the subscript 3.

Then #"Fe"_2("SO"_4)_3# becomes #"Fe"_2"S"_3"O"_12#.

Now, we can calculate the formula mass.

#bb("No."color(white)(m)"Atom"color(white)(mm)A_text(r)color(white)(mm) "Mass")#
#color(white)(l)2color(white)(mmml)"Fe"color(white)(mml)55.84color(white)(mll)111.68#
#color(white)(l)3color(white)(mmml)"S"color(white)(mmm) 32.06color(white)(mm)96.18#
#12color(white)(mmm)"O"color(white)(mmll)16.00color(white)(mll)192.00#
#color(white)(mmmmmmmll)"Total = 399.86"#

The formula mass is 399.86 u.