PLEASE HELP SOMEONE

Kc = 0.040 for the system below at 450oc. if a reaction is initiated with 0.40 mole of cl2 and 0.40 mole of pcl3 in a 2.0 liter container, what is the equilibrium concentration of cl2 in the same system? pcl5(g) ⇄ pcl3(g) + cl2(g)

If 1.8 l of water is added to 2.5l of a 7.0 m koh solution, what is the molarity of the new solution

How many neutrons does an element have if its atomic number is 50 and its mass number is 166