the following procedure may be used to determine the density of a granular material. A sample of a granular material weighing 4.35 grams is placed in a 15 mL flask and then completely filled with benzene (liquid) the density of which is .879g/cc. The granular material and benzene together weigh 17.33 grams. What is the density of the granular material? (IT doesn't dissolve in benzene)

Question

what formulas would i use for this?

Answer 1

mass unknown = 4.35 grams.
density = mass/volume. All of this information must be manipulated to provide a volume of the unknown.
IF the flask has a volume of 15 mL (and most flasks are NOT calibrated at all--a graduated cylinder would be better), then mass benzene is 17.33-4.35 so the volume of the benzene used to fill the flask is 12.98/0.879 = ?? That is the volume of the benzene; the difference between that and 15 is the volume occupied by the unknown. Substitute that volume into the secopnd line of this post to calculate density of the unknown.