Question

The compound phosphine, PH3, is produced by rotting corpses (the human body is about 1.0% by mass phosphorus); its spontaneous ignition in air above graveyards gave rise to legends such as the will-othe-wisps: 20 pts. 4 ( ) 8 ( ) ( ) 6 ( ) 3 2 4 10 2 PH g + O g → P O s + H O l  ∆H f (PH3) = +5.40 kJ/mol;  ∆H f (P4O10) = –2984 kJ/mol  ∆H f (H2O(l)) = –285.8 kJ/mol ;

Calculate the following quantities:

(1)  ∆Hrxn for the balanced stoichiometric reaction (the recipe reaction); ∆Ho = __________ kJ

(2)  ∆H when 0.94 kg of phosphine are the limiting reagent; ∆Hº = __________kJ

(3) q for the reaction when 0.94 kg of phosphine are the limiting reagent assuming constant pressure; q = _________ kJ

(4) the work, w, for the reaction when 0.94 kg of phosphine are the limiting reagent; assume T = 290K.