How do I find the mass of potassium in a #50.0*g# mass of potassium sulfate?

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Answer 1 · 2015-09-07T15:51:16

Divide the mass by the molar mass.

Molecular mass #"K"_2"SO"_4 = "174.26 g·mol"^-1#.

You can find this by adding the atomic masses of all the atoms that make up the molecule -- you can find these in the periodic table.

You have #"50.0 g"#.

Divide the second value by the first.

#(50.0 color(red)(cancel(color(black)("g"))))/(174.26 color(red)(cancel(color(black)("g")))"·mol"^-1)= "0.287 mol"# of #"K"_2"SO"_4#

Now remember to multiply this answer by #2#, because there are two #"K"#-atoms per molecule, so the final answer is #0.574mol# of #"K"#