Heats of formation and bond energies. Part XIV. Heat of combustion of arsenic

Abstract

The heat of combustion of arsenic (α, rhomb. cryst.,) in oxygen has been measured in a rotating-bomb calorimeter charged with an aqueous solution of sodium hydroxide, when the products of combustion are sodium arsenite and sodium arsenate, in aqueous solution. Incorporating data for the heat of reduction of sodium arsenate to sodium arsenite and the heat of solution of arsenious oxide in an aqueous solution of sodium hydroxide, the value ΔH_f°(As₂O₃, octa., cryst.)=–160·0 ± 3·0 kcal./mole is obtained.