4. Which of the following has an enthalpy of formation that is equal to zero? A) O(g) B) H2O(i) C) O2(g) D) H+(aq) E) All of these have nonzero enthalpies of formation. 5. For which of the following reactions is Kc=Kp at all temperatures? A) C(s)+CO2(g)2CO(g) B) C(s)+2H2O(g)CO2(g)+2H2(g) C) CO2(g)+H2(g)CO(g)+H2O (g) D) H2(g)+1/2O2(g)H2O(g) E) Ca(s)+1/2O2(g)CaO(s) 6. Shown at right is the phase diagram of CO2. What state(s) of matter will be present at equilibrium at 5.11atm and 56.4C ? Write the letters of ALL that apply. A) solid B) liquid C.) gas D) supercritical fluid E) Not enough information to say SHORT ANSWER 6. (12 points) Calculate Hm for the reaction 2OF2(g)+SO2(g)SF(g)+2O2(g) using the following data: OF2(g)+H2O(l)O2(g)+2HF(g)SF4(g)+2H2O(l)4HF(g)+SO2(g)Hmol=276.6kJ/molHm=827.5kJ/mol