Applications of Thermodynamics

The metal components within the engine naturally conduct external heat from the environment.

Friction between moving parts of the engine generates significant amounts of heat energy.

Endothermic reactions absorb heat from the surroundings, heating up the metal casing of the engine.

The engine's operation involves exothermic chemical reactions that release heat.

negative

zero

positive

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Varying the color of light passing through the reaction mixture.

Altering the partial pressures of gaseous reactants and products.

Switching the type of material used as a container for the reaction.

Changing the concentration of solid catalysts in the system.

ΔH° is negative

ΔH° is undefined

ΔH° is positive

ΔH° is zero

Heat capacity (Cp)

Entropy (S)

Internal energy (U)

Enthalpy (H)

Shifts equilibrium toward reactants to increase pressure

Immediately increases product concentration without shifting equilibrium

Has no effect on equilibrium position since only concentration matters

Shifts equilibrium toward products to decrease pressure

No condition makes the reaction spontaneous

Under standard conditions

At low temperatures

At high temperatures

Microstates multiplicities increase during compression, raising positional momenta, which impacts negatively on ΔG.

Vibration speed of molecules enhances dramatically, shifting the equilibrium position and altering K but negligibly affecting ΔG.

The number of collisions per unit time goes up, converting kinetic forms of heat, affecting ΔH but not necessarily ΔG.

Rotational degrees of freedom become more accessible, thereby incrementing internal energies yet scarcely modifying ΔG.

H

G

S

E

Total energy of the system remains constant throughout the reaction.

The entropy of the system increases more than enough to compensate for the increase in enthalpy.

The change in Gibbs free energy (ΔG) must equal zero.

The equilibrium constant (K) must be greater than one.