Thermochemistry Fundamentals
Explore the basic principles of thermochemistry, including enthalpy, entropy, Gibbs free energy, and Hess's Law.
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Thermochemistry Fundamentals
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Read each question carefully and answer to the best of your ability. Show all your work for calculation problems.
1. Which of the following statements correctly defines enthalpy?
The measure of disorder in a system.
The total heat content of a system at constant pressure.
The energy required to initiate a chemical reaction.
The change in volume of a gas at constant temperature.
2. An endothermic reaction is characterized by:
Release of heat to the surroundings.
Absorption of heat from the surroundings.
No change in heat content.
Increase in kinetic energy only.
1. Hess's Law states that the total enthalpy change for a reaction is independent of the taken.
2. A spontaneous process is one that occurs without continuous intervention, often driven by an increase in of the universe.
1. The standard enthalpy of formation for an element in its most stable form is zero.
True
False
2. An increase in temperature always leads to a decrease in entropy.
True
False
1. Explain the difference between an open system, a closed system, and an isolated system in thermodynamics.
2. State the First Law of Thermodynamics and provide an example of its application.
Calculate the standard enthalpy change (ΔH°) for the following reaction using the given standard enthalpies of formation (ΔH°f):
2 SO₂(g) + O₂(g) → 2 SO₃(g)
Given:
ΔH°f (SO₂(g)) = -296.8 kJ/mol
ΔH°f (SO₃(g)) = -395.7 kJ/mol