Question

What is the formula weight (molar mass) of a compound if 20 g of the compound in 500 mL of solution gives a 0.5 M solution?

Answer 1

The  molar  mass  of  a  compound    is  calculated  as  below

find the number of  moles

moles=  molarity  x volume/1000

=500  ml  x0.5 /1000 =  0.25  moles

molar mass  is  therefore=  mass/number  of  moles

=  20/0.25 =  80  g/mol