can someone help? im really struggling with this problem

Question

if you have a 155 ml solution of a 0.762 m FeCl3 solution, how many G FeCl3 are contained in this sample?

Answer 1

0.762 M means 0.762 moles/liter and since there are 0.155 liters (155ml/1000 ml/l = 0.155 L) then there are (0.762)(0.155) = 0.11811 moles of FeCl₃.

To determine the mass of it, we need to multiply by the molar mass. To calculate the molar mass, look up Iron and Chlorine in the periodic table:

Iron (Fe) = 55.845 g/mol

Chlorine (Cl) = 35.453(3) = 106.359 g/mol

FeCl₃ = 55.845 + 106.359 = 162.204 g/mol

So the mass of FeCl₃ is (0.11811 moles)(162.204 g/mol) = 19.2 grams