# Problem: For each of the following reactions, identify another quantity that is equal to Δ°Hrxn. 1. CH4(g) + 2O2(g) →CO2(g) + 2H2O(l) a) enathalpy of combustion of CH4b) enthalpy of formation of CO2(g)c) 4x bond energy of C - H d) - 4x bond energy of C - H 2. CH4(g) → C(g) + 4H(g)  a) enathalpy of combustion of CH4b) enthalpy of formation of C(g)c) 4x bond energy of C - H d) - 4x bond energy of C - H 3. C(graphite) + 2H2(g) → CH4(g) a) enathalpy of combustion of CH4b) enthalpy of formation of CH4(g)c) 4x bond energy of C - H d) - 4x bond energy of C - H 4. C(g) + 4H(g) → CH4(g) a) enathalpy of combustion of Cb) enthalpy of formation of CH4(g)c) 4x bond energy of C - H d) - 4x bond energy of C - H

###### FREE Expert Solution

Δ°H rxn = Δ°H products - Δ°H reactants

1. CH4(g) + 2O2(g) →CO2(g) + 2H2O(l)

a) enthalpy of combustion of CH4   (correct combustion reaction for CH4)

b) enthalpy of formation of CO2(g) (incorrect, reaction is not a formation reaction; incorrect)

c) 4x bond energy of C - H  (bond breaking and formation is not included; incorrect)

d) - 4x bond energy of C - H  (bond breaking and formation is not included; should be positive; incorrect)

2. CH4(g) → C(g) + 4H(g)

a) enthalpy of combustion of CH4  (not a combustion reaction; incorrect)

b) enthalpy of formation of C(g) (C is already in standard state; incorrect)

c) 4x bond energy of C - H (C-Hs are being broken; correct answer)

d) - 4x bond energy of C - H (must be positive; incorrect)

95% (424 ratings) ###### Problem Details

For each of the following reactions, identify another quantity that is equal to Δ°Hrxn

1. CH4(g) + 2O2(g) →CO2(g) + 2H2O(l)

a) enathalpy of combustion of CH4

b) enthalpy of formation of CO2(g)

c) 4x bond energy of C - H

d) - 4x bond energy of C - H

2. CH4(g) → C(g) + 4H(g)

a) enathalpy of combustion of CH4

b) enthalpy of formation of C(g)

c) 4x bond energy of C - H

d) - 4x bond energy of C - H

3. C(graphite) + 2H2(g) → CH4(g)

a) enathalpy of combustion of CH4

b) enthalpy of formation of CH4(g)

c) 4x bond energy of C - H

d) - 4x bond energy of C - H

4. C(g) + 4H(g) → CH4(g)

a) enathalpy of combustion of C

b) enthalpy of formation of CH4(g)

c) 4x bond energy of C - H

d) - 4x bond energy of C - H