A graduate student needs to prepare isotopically labeled phosgene gas, 13COCl2, for use in the synthesis of an organic compound (all the C atoms are carbon-13). The students place 3.59 atm of 13CO (g) and 2.75 atm of Cl2 (g) in a steel cylinder at 25 ̊C, seals the cylinder, and heats it to 227 ̊C. After the cylinder is kept at the elevated temperature for a week, the pressure inside the cylinder is found to be 9.75 atm while still at 227 ̊C. 

(a) What are the mole fractions of 13CO, Cl2, and 13COCl2 present in the vessel at the end of the week? 

(b) What is the density of the mixture