The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ) released to the surroundings when 38.5 g of O2 (g) reacts with excess CO? 2CO (g) + O2 (g) → 2CO2 (g) a.2.65 × 10 3 kJ b.482 kJ c.580. kJ d.65.7kJ

1 Answer
Apr 6, 2018

Consider,

#2CO(g) + O_2(g) to 2CO_2(g)# where #DeltaH^o = -(482"kJ")/"mol"#

Think of the reaction releasing that much heat per stoichiometric equivalent of reactants. If the limiting reactant is oxygen gas, it will increase the enthalpy of reaction by a factor equal to the molar amount of oxygen.

Hence,

#38.5"g" * (O_2)/(32"g") * (-482"kJ")/"mol" approx -580"kJ"#

are released from the system, and #DeltaH_"surr" = -DeltaH_"sys"#, so the heat released would be opposite in direction, but equal in magnitude to that value.

Answer: #"C"#.