Question

What mass ( g ) of the solvent chloroform that should be added with 5287 mL of the solute hexane to produce a solution that is 7.11 m hexane.

Answer 1

Look up the density of hexane and chloroform. Use the density to convert 6287 mL hexane to grams.
Then moles hexane = grams/molar mass.
m = moles hexane/kg CHCl3.
You know m and you know moles, calculate kg CHCl3.