A.) Calculate the bond energy per mole for forming all the bonds of water molecu

Question

A.) Calculate the bond energy per mole for forming all the bonds of water molecules, H2O.

Express your answer to three significant figures and include the appropriate units.

HH2O =???

B.) Calculate the bond energy per mole for forming all the bonds of carbon dioxide, CO2.

Express your answer to four significant figures and include the appropriate units.

HCO2 = ???

Bond Energies and Enthalpy of the Reaction

Hrxn=(Hbreaking)+(Hforming)

where H represents bond energies for the breaking (positive bond energy) or forming (negative bond energy) of a bond and Hrxn represents the overall enthalpy for the reaction.

Use the table to answer questions about bond energies.

Bond Energies and Enthalpy of the Reaction

In chemical reactions, heat is converted into chemical energy (the potential energy stored in chemical bonds) or vice versa. Bond energy is the energy required to break one mole of the bond in the gas phase. Since it takes energy to break a bond, bond energies are always positive. Conversely, energy is released when bonds are formed. Thus, the enthalpy change for a reaction can be approximated from

Hrxn=(Hbreaking)+(Hforming)

where H represents bond energies for the breaking (positive bond energy) or forming (negative bond energy) of a bond and Hrxn represents the overall enthalpy for the reaction.

Use the table to answer questions about bond energies.

Bond Bond energy
(kJ/mol ) CC 347 C=C 611 CH 414 CO 360 C=OinCO2 799 OO 142 O=O 498 HO 464

Explanation / Answer

A = H2O = -2* 464 = -928 Kj/mol

B = co2 = 2*799 = - 1598 kj/mol

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