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# 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)

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###### 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

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Formation Equations concept. You can view video lessons to learn Formation Equations. Or if you need more Formation Equations practice, you can also practice Formation Equations practice problems.

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Our tutors rated the difficulty ofFor each of the following reactions, identify another quanti...as medium difficulty.