PChem Thermo Final

equipartition theorem

The _______________________________________ states that for a sample at thermal equilibrium, the average value of each quadratic contribution to the energy is (1/2)kT

does not change

The internal energy of an ideal gas \________________ as volume occupied increases.

infinitesimal

A reversible change is a change that can be reversed by an
\_________________________ change in a variable.

no

Does the free expansion (expansion against zero pressure) of a
non-ideal gas do work?

enthalpy with respect to temperature, pressure

The constant-pressure heat capacity is the partial derivative of ____________________________________ with _____________ constant.

differential scanning calorimeter

The type of calorimeter that measures energy transferred as heat
to or from a sample compared to that of a reference material is called a what?

all of the above

Changes in enthalpy accompany which of the following: formation, mixing, sublimation, or all of the above?

all of the above

The Joule-Thomson coefficient of a non-ideal gas can be zero, positive, negative, or all of the above?

decreases

When an ideal gas expands adiabatically and it does work, its temperature ___________________.

Cp,m=Cv,m+R

What is the value of Cp,m relative to Cv,m?

isolated, increases

The 2nd Law of Thermodynamics states that the entropy of a(n) _______________ system _____________ in the course of a spontaneous change.

at equilibrium

Processes accompanied by no change in entropy are _________________________.

dS=dH/T

How is entropy change at transition temperature related to enthalpy change at that temperature?

Cp and Cv

What values govern how entropy increases with increasing temperature?

Debye extrapolation

What method is used to estimate heat capacities of non-metallic solids close to T=0?

all of the above

Changes in entropy accompany which of the following: formation, mixing, sublimation, or all of the above?

residual entropy

____________________ is a non-zero entropy at T=0 arising from molecular disorder.

translation, rotation, vibration, and electronic

Which energetic DOF can contribute to molecular entropy?

molar volume, temperature

An increase in either ________________ or ____________________ can cause the molar entropy of a monatomic gas to increase.

heavy gases

Do heavy or light gases have a larger molar entropy at 298 K?

dA_T,V

What three criterions are true for spontaneous changes?

solvation

The Born equation calculates the Gibbs free energy of _________________ for an ion.

dU=TdS-pdV

What is the fundamental equation of thermodynamics?

decreases, increases

The Gibbs energy of a substance ________________ with temperature and _________________ with pressure.

temperature, enthalpy

The Gibbs-Helmholtz equation describes how the variation of Gibbs energy with _______________ is related to the _______________.

number of thermally accessible states

The thermodynamic tendency to lower Gibbs energy can be seen to be a tendency to maximize the ________________________________________________________________.

entropy, surroundings

In dA=dU-TdS, dA indicates spontaneity under constant volume and temperature and dU is related to the _______________ change of the _____________________.

0 kJ/mol

The standard Gibbs energy of oxygen at 298 K is ___________.

increases

The chemical potential of a substance _________________ when pressure is increased.

solid

The chemical potential changes the least when temperature changes for which phase of a substance?

increases

When pressure is applied to a condensed phase, the vapor pressure ________________.

less than

When water and ethanol are mixed, the partial molar volume of ethanol is (less than/more than) the partial molar volume of pure ethanol.

Gibbs-Duhem equation

Which equation expresses the fact that the chemical potential of one component of a mixture cannot change independently of the chemical potentials of the other components?

freezing point depression, boiling point elevation, vapor pressure lowering, osmotic pressure

What are the 4 colligative properties?

mole fraction

Colligative properties depend on the _________________________ of the solute.

liquid solvent

Colligative properties arise from the reduction in the chemical potential of the ___________________________.

critical temperature

The temperature at which the densities of the vapor phase and the liquid are equal and there is no interface between the two phases is called the _________________________________________.

dH_trs

What quantity is assumed to be independent of temperature in the Clausius-Clapeyron equation?

zero

The enthalpy of mixing of two ideal gases is _____________.

zero

The entropy change of the surroundings when two ideal gases mix is ___________.

exergonic

Reactions with a negative dG_rxn are classified as ______________________.

dG_rxn

The forward reaction in an equilibrium equation is spontaneous if __________________.

reaction quotient

The ratio of activities of products to activities of reactants is what?

p/p^o

The activity of a gas can be approximated by _________.

decreases

K for an exothermic reaction ______________ when temperature increases.

the effect of the disturbance

Le Chatelier's principle states that "A system at equilibrium, when subjected to a disturbance, tends to respond in a way that minimizes ________________________________________.

probability

Normalizing the wavefunction makes the __________________________ over all space = 1.

24\.8 J/Kmol

What is the molar volume of an ideal gas at 298 K and 1 bar?

increases

The molecular partition function, q, increases when temperature _________________.

F=-dV/dx

What is the mathematical relationship between the potential and the force?

translation

Which contribution to the partition function is the largest for a molecule at a given temperature?

temperature

What parameter governs the most probable populations of states of a system at thermal equilibrium?

electronic, rotational, and translational

For which energetic DOF can states of a molecule be degenerate?

attractive and repulsive forces

The second virial coefficient, B2v, accounts for __________________________________________________ between atoms/molecules.

soft sphere

Which model representing interactions between molecules includes attraction?

coupling with rotation

A deficiency in the harmonic oscillator model for vibration is that it ignores ______________________________.

bonds don't stretch

A deficiency in the rigid rotor model is it assumes what?

temperature

The most populated rotational energy level for a diatomic depends on what?

ensemble partition function

The _________________________________ is a function of the number of molecules in the ensemble.

eigenvalue, eigenfunctions

If a wavefunction can be written as a linear combination of eigenfunctions of an operator, measurement of the property associated with that operator yields an _______________________ associated with one of the ______________________.

Pauli principle

The symmetry number used to calculate rotational partition function results from symmetry requirements imposed by the ______________________________.

temperature and vibrational frequency

C_V,m of a diatomic molecule at 298 K is a function of what two variables?

constant

The potential energy of a particle on the surface of a sphere is ______________.

increase

As diatomics have increasingly more electrons, do their C_V,m values increase or decrease?

0

for an isothermal expansion of an ideal gas, what is the change in internal energy?

w=-nRTln(V2/V1)

for an isothermal, reversible expansion of an ideal gas, what is the work?

w=-p_exdV

for an isothermal expansion against constant external pressure, what is the work?

w=0

for an isothermal expansion against zero external pressure, what is the work?

q=nC_pdT

what is q when an ideal gas is heated at constant pressure?

dH=q_p

what is dH when an ideal gas is heated at constant pressure?

dU=dH-nRdT

what is the change in internal energy when an ideal gas is heated at constant pressure?

dH=dU+d(pV)

what is the formula for dH for an ideal gas?

temperature, pressure, enthalpy

the Joule-Thomson coefficient is the change in ________________ wrt the change in _______________ when ______________ is held constant

dS=nRln(p1/p2)+nC_pln(T2/T1)

What is the change in entropy when an ideal gas undergoes changes in both temperature and pressure?

dS=nRln(V2/V1)

What is the change in entropy when an ideal gas undergoes isothermal, reversible expansion?

dS_surr=-q/T

What is the change in entropy for the surroundings when an ideal gas undergoes isothermal, reversible expansion?

dS_surr=0

What is the change in entropy for the surroundings when an ideal gas undergoes isothermal, irreversible expansion against p_ex=0?

dG=-nRTln(V2/V1)

What is the change in Gibbs energy for an ideal gas expanding isothermally?

\-S_m

What is the slope of the plot of chemical potential vs temperature when pressure is held constant?

V_m

What is the slope of the plot of chemical potential vs pressure when temperature is held constant?

1 atm

At what pressure is the temperature equal to the normal boiling point?

\-dH_vap/R

What is the slope of a plot of ln(p) vs 1/T?

dT=iKm

What is the change in the freezing/boiling point formula?

dG=-RTlnKp

What is the formula for standard dG_rxn?

reversible

maximum expansion work of a gas is obtained from what kind of expansion?

positive, negative

an ideal gas that expands spontaneously against constant external pressure and increasing temperature has a ____________ change in entropy for the system and a ______________ change in entropy for the surroundings.

constant pressure and temperature

the change in G indicates direction of spontaneity under which conditions?

dU+pdV+Vdp

What is the total differential for the enthalpy, H?

dH-TdS-SdT

What is the total differential for the Gibbs free energy, G?

dS=-dG/T

What is the change in entropy, in terms of dG, when an ideal gas undergoes an irreversible isothermal expansion?

no

Does Kp depend on pressure?

b

What variable in the VDW equation represents effective volume?

a

What variable in the VDW equation represents attractive forces?

U vs. T

What plot has the constant-volume heat capacity as its slope?

H vs. T

What plot has the constant-pressure heat capacity as its slope?

heating

negative Joule-Thomson coefficients represent gases with a ______________ effect

cooling

positive Joule-Thomson coefficients represent gases with a _____________ effect

dq_rev=0

what value makes a process adiabatic?

less, more

for a real gas, Z is _____________ than 1 at low pressures are Z is ______________ than 1 at high pressures

increases

when the temperature of an ideal gas increases, internal energy _________________