How many moles are in a 60 gram sample of NaCl

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

Solid tin exists in two forms: white and gray. for the transformation sn(s, white) → sn(s, gray) the enthalpy change is -2.1 kj/mol and the entropy change is -7.4 j/(mol*k). a. calculate the gibbs free energy change for the conversion of 1.00 mol white tin to gray tin at -30℃. b. will white tin convert spontaneously to gray tin at -30℃? c. at what temperature are white and gray tin thermodynamically equivalent at a pressure of 1 atm?

Someone do this for me. im really stuck