Consider the intermediate equations: 3 equations. 1: upper C solid plus upper o subscript 2 gas right arrow upper C upper O subscript 2 gas Delta H 1 equals negative 393.5 kilojoules. 2: 2 upper C upper O gas plus upper O subscript 2 gas right arrow 2 upper C upper O subscript 2 gas Delta H 2 equals negative 566.0 kilojoules. 3: 2 upper H subscript 2 upper o gas right arrow 2 upper H subscript 2 gas plus upper O subscript 2 gas delta H 3 equals 483.6 kilojoules. With the overall reaction: Upper C (s) plus upper H subscript 2 upper O (g) right arrow upper C upper O (g) plus upper H subscript 2 (g). What must be done to calculate the enthalpy of reaction