Find the heat of reaction for this target reaction: CO2(g) + H2O(l) → C12H22O11(s) + O2(g) (unbalanced)

Question

Given the following data:

∆Hf Values of Selected Chemicals (kJ/mol)

C12H22O11(s) = -2222.31

CO2(g) = -393.5

H2O(g) = -241.826

CO(g) = -110.5

H2O(l) = -285.840

O2(g) = ?

Fill in the missing value

Answer 1

Hess' Law

12CO₂(g) + 11H₂O(l) ==> C₁₂H₂₂O₁₁(s) + 12O₂(g) ... BALANCED TARGET EQUATION

Given ∆Hf values (I'm assuming these are standard values, i.e.∆Hº):

C₁₂H₂₂O₁₁(s) = -2222.31

CO₂(g) = -393.5

H₂O(g) = -241.826

CO(g) = -110.5

H₂O(l) = -285.840

O₂(g) = 0 (even though not given, we know that is ∆Hf for O₂ since it is in its elemental state)

∆Hºrxn = ∑n∆Hproducts - ∑n∆Hreactants

∆Hºrxn = (-2222.31 + 0) - [(12)(-393.5) + (11)(-285.840)]

∆Hºrxn = -2222.31 - (-4722) + (-3144.24) = -2222.31 - (-7866.24)

∆Hºrxn = 5644 kJ