I was able to find the final pressure using (P1*V1)/ T1 = (P2*P2)/T2 equation. However, I am not sure how to find how many grams of chlorobenzene. I guess I should use density and 50 ppmv, but have not figured how to use it. I think with the known grams of chlorobenzene, I can find the number of moles and the volumes needed. Am I on the right track?