Acetylene 1C2H22 and nitrogen 1N22 both contain a triplebond, but they differ greatly in their chemical properties.(a) Write the Lewis structures for the two substances. (b) Byreferring to Appendix C, look up the enthalpies of formationof acetylene and nitrogen. Which compound is more stable?(c) Write balanced chemical equations for the completeoxidation of N2 to form N2O51g2 and of acetylene to formCO21g2 and H2O1g2. (d) Calculate the enthalpy of oxidationper mole for N2 and for C2H2 (the enthalpy of formationof N2O51g2 is 11.30 kJ>mol). (e) Both N2 and C2H2 possesstriple bonds with quite high bond enthalpies (Table 8.3).Calculate the enthalpy of hydrogenation per mole for bothcompounds: acetylene plus H2 to make methane, CH4;nitrogen plus H2 to make ammonia, NH3.
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
Acetylene 1C2H22 and nitrogen 1N22 both contain a triple
bond, but they differ greatly in their chemical properties.
(a) Write the Lewis structures for the two substances. (b) Byreferring to Appendix C, look up the enthalpies of formation
of acetylene and nitrogen. Which compound is more stable?
(c) Write balanced chemical equations for the complete
oxidation of N2 to form N2O51g2 and of acetylene to form
CO21g2 and H2O1g2. (d) Calculate the enthalpy of oxidation
per mole for N2 and for C2H2 (the enthalpy of formation
of N2O51g2 is 11.30 kJ>mol). (e) Both N2 and C2H2 possess
triple bonds with quite high bond enthalpies (Table 8.3).
Calculate the enthalpy of hydrogenation per mole for both
compounds: acetylene plus H2 to make methane, CH4;
nitrogen plus H2 to make ammonia, NH3.
Trending now
This is a popular solution!
Step by step
Solved in 4 steps with 7 images
