# Chemical Thermodynamics

## Presentation on theme: "Chemical Thermodynamics"— Presentation transcript:

Chemical Thermodynamics
Chemistry, The Central Science, 11th edition Theodore L. Brown, H. Eugene LeMay, Jr., Bruce E. Bursten, and Catherine J. Murphy Chapter 19 Chemical Thermodynamics Dana & Michelle Chatellier University of Delaware © Copyright 2009, Pearson Education

The first law of thermodynamics states that __________ is conserved.
matter energy entropy temperature

The first law of thermodynamics states that __________ is conserved.
matter energy entropy temperature

Which process is NOT spontaneous at 25 °C?
the melting of an ice cube the sublimation of dry ice the boiling of liquid nitrogen the freezing of ethyl alcohol

Which process is NOT spontaneous at 25 °C?
the melting of an ice cube the sublimation of dry ice the boiling of liquid nitrogen the freezing of ethyl alcohol

Entropy is a measure of the __________ of a system.
randomness internal energy temperature polarity

Entropy is a measure of the __________ of a system.
randomness internal energy temperature polarity

Since entropy is a state function, the change in entropy is equal to its final value __________ its initial value. plus minus multiplied by divided by

Since entropy is a state function, the change in entropy is equal to its final value __________ its initial value. plus minus multiplied by divided by

Boltzmann’s constant = k. The number of microstates = W. Entropy = S
Boltzmann’s constant = k. The number of microstates = W. Entropy = S. Which is correct? S = k x W S = k / W S = k ln W S = kW

Boltzmann’s constant = k. The number of microstates = W. Entropy = S
Boltzmann’s constant = k. The number of microstates = W. Entropy = S. Which is correct? S = k x W S = k / W S = k ln W S = kW

Entropy decreases when:
gases are formed from liquids. liquids are formed from solids. solids are formed from gases. the number of gas molecules increases during a chemical reaction.

Entropy decreases when:
gases are formed from liquids. liquids are formed from solids. solids are formed from gases. the number of gas molecules increases during a chemical reaction.

The second law of thermodynamics states that entropy __________ as a result of an irreversible process. increases decreases remains unchanged reaches equilibrium

The second law of thermodynamics states that entropy __________ as a result of an irreversible process. increases decreases remains unchanged reaches equilibrium

The third law of thermodynamics states that the entropy of a pure, perfect crystalline substance at absolute zero (0 K) is: infinite. increasing. decreasing. zero.

The third law of thermodynamics states that the entropy of a pure, perfect crystalline substance at absolute zero (0 K) is: infinite. increasing. decreasing. zero.

H = enthalpy. S = entropy. T = Kelvin temperature
H = enthalpy. S = entropy. T = Kelvin temperature. The Gibbs free energy, G, is: H + TS H – TS H x TS H / TS

H = enthalpy. S = entropy. T = Kelvin temperature
H = enthalpy. S = entropy. T = Kelvin temperature. The Gibbs free energy, G, is: H + TS H – TS H x TS H / TS

The value of ∆G, the Gibbs free energy change, for a system at equilibrium is:
positive. negative. rapidly fluctuating from positive to negative. zero.

The value of ∆G, the Gibbs free energy change, for a system at equilibrium is:
positive. negative. rapidly fluctuating from positive to negative. zero.

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