Enthalpy, entropy, Gibbs free energy, and the laws of thermodynamics as applied to chemical reactions tested on the MCAT.
35 cards · basic cards · AI-written, checked twice. Edit anything.
- What does the first law of thermodynamics state?
- Energy cannot be created or destroyed, only transformed or transferred
- What is the formula for the change in internal energy according to the first law of thermodynamics?
- Delta U = Q - W (heat added minus work done by the system)
- What does enthalpy (H) represent?
- The heat content of a system at constant pressure
- What is the sign of the enthalpy change in an exothermic reaction?
- Negative
- What is the sign of the enthalpy change in an endothermic reaction?
- Positive
- What law states that the total enthalpy change of a reaction is the same whether it occurs in one step or multiple steps?
- Hess's law
- What does entropy (S) measure?
- The degree of disorder or randomness in a system
- What does the second law of thermodynamics state about the entropy of an isolated system?
- The entropy of an isolated system tends to increase over time
- What does the third law of thermodynamics state about a perfect crystal at absolute zero?
- Its entropy is exactly zero
- What is the formula for Gibbs free energy in terms of enthalpy, entropy, and temperature?
- Delta G = Delta H - T(Delta S)
- What does a negative Gibbs free energy (Delta G < 0) indicate about a reaction?
- The reaction is spontaneous under the given conditions
- What does a positive Gibbs free energy (Delta G > 0) indicate about a reaction?
- The reaction is nonspontaneous under the given conditions
- Under what condition of Gibbs free energy is a reaction at equilibrium?
- Delta G = 0
- How does temperature affect spontaneity when Delta H is positive and Delta S is positive?
- The reaction becomes spontaneous at high temperatures
- What thermodynamic quantity describes the heat required to raise the temperature of a substance by one degree?
- Heat capacity
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