How are fossil fuels formed? A. Volcanoes erupt, bringing up energy from underground. B. Plants and animals decompose underground. C. Fossils combust and release petroleum D. The sun sends energy to Earth.

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)