Calculate the enthalpy change for the reaction CaCO3(g)→CaO(s)+CO2(g) , from the following equations: 2Ca(s)+O2(g)→2CaO(s) ΔH=−1270kJ 2Ca(s)+2C(s)+3O2(g)→2CaCO3(s) ΔH=−2414kJ C(s)+O2(g)→CO2(g) ΔH=−394kJ

Which of the following reactions represents an exothermic reaction? nh3(g) + 12.0 kcal ½n2(g) + 3/2 h2(g) ch4 + 2o2 co2 + 2h2o + 212,800 cal c + 2s cs2, h = 27,550 cal c(graphite) c(diamond), h = 0.45 kcal 2h2o 2h2 + o2, h = +58 kcal