Gibbs Free Energy Formulas Explained
Gibbs free energy ($G$) represents the maximum amount of non-expansion work that can be extracted from a closed system at constant temperature and pressure. It is a thermodynamic potential.
We need to identify which given expression does not correctly represent Gibbs free energy ($G$).
Thermodynamic Relationships
Key thermodynamic relationships are:
- Internal Energy: $U$
- Enthalpy: $H = U + PV$
- Helmholtz Free Energy: $F = U - TS$
- Gibbs Free Energy: $G = H - TS$
Analyzing the Options
Let's examine each option based on the definition $G = H - TS$ and the relationship $H = U + PV$.
-
Option 1: $G = U + TS$
This expression is not a standard formula for Gibbs free energy. It resembles the Helmholtz free energy formula ($F = U - TS$) but with a positive sign for the $TS$ term. -
Option 2: $G = F + PV$
Substitute $F = U - TS$: $G = (U - TS) + PV$ $G = U - TS + PV$ This matches a known form of Gibbs free energy. -
Option 3: $G = H - TS$
This is the fundamental definition of Gibbs free energy. -
Option 4: $G = U - TS + PV$
Substitute $H = U + PV$ into the definition $G = H - TS$: $G = (U + PV) - TS$ $G = U - TS + PV$ This is a valid expression for Gibbs free energy.
Conclusion on Gibbs Free Energy Representation
Options 2, 3, and 4 represent valid forms of Gibbs free energy ($G$). Option 1, $G = U + TS$, does not represent Gibbs free energy.
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Important Questions from Mixed Topic (CUET PG)
- Who was the founder of Bolshevik Communist party?
- What is the key guide to statecraft in the realist tradition?
- Chronologically arrange the events in the Cold War period.
A. Berlin Wall is constructed
B. Communist China joins the UN
C. Soviet invasion of Czechoslovakia
D. Berlin Blockade
Choose the correct answer from the options given below: Morgenthau's principles of political realism are:
A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
C. International Politics is an arena of conflicting self-interests
D. The ethics of international relations is situational ethics which is very different from private morality
Choose the correct answer from the options given below:Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?
