Initial idea which is believed to be true

The first element on the periodic table of elements is carbon. a. true b. false

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)

Joan writes four numbers on the board in standard form, and then she writes their scientific notation