C2H5OH+ 3O2→ 2CO2 + 3H2O ΔHc= -1368kJ/mol (H1=enthalpy of reactant)while (H2 enthalpy of products) for this reaction
Correct answer: B. H1 > H2
- A. H2 > H1
- B. H1 > H2
- C. H1 = H2
- D. No relationship
Explanation
he information provided reveals two crucial aspects:The reaction is exothermic: The enthalpy change (ΔHc) is negative (-1368 kJ/mol). This indicates that energy is released to the surroundings during the reaction.H1 refers to the enthalpy of reactants, and H2 refers to the enthalpy of products.In an exothermic reaction, the products have a lower overall enthalpy compared to the reactants. This aligns with the law of conservation of energy: if energy is released (exothermic), the energy stored in the products (H2) must be less than the energy stored in the reactants (H1).Key Points:In an exothermic reaction, ΔHc is negative, and the products have lower enthalpy than the reactants.H1 > H2 reflects this relationship.Options (a), (c), and (d) are incorrect because they contradict the fundamental principles of exothermic reactions.
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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