. Look at the periodic table, how much does one mole of a Hydrogen atom weigh? Why is the molar mass of hydrogen (H2) 2.02 g/mol in the example 1 above?

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)