Physical Chemistry (Group 1)

Front 1

P = __ / A

Back 1

P = F / A

Front 2

What is the SI unit of pressure?

Back 2

Pascal

Front 3

What is the standard pressure? What is the symbol for standard pressure?

Back 3

Standard pressure equals 1 bar (10^5 Pa) and its symbol is p.

Front 4

How is pressure expressed in terms of density, gravity, and height?

Back 4

p = ρgh

Front 5

Summarize Boyle's Law

Back 5

pressure (p) is inversely proportional to volume (V). pV=R, or p∝1/V

If a sample of gas is compressed to half its volume, twice as many molecules strike the walls, so pressure doubles

Front 6

Summarize Charles' Law

Back 6

volume (V) is proportional to temperature (T). V = RT

Raising the temperature of a gas increases avg speed of molecules, so they hit the walls more frequently and with greater impact

Front 7

Summarize Avogadro's principle

Back 7

Equal volumes of gases at the same temperature and pressure contain the same numbers of molecules (volume (V) is proportional to number of moles (n)).

Front 8

__________ is a collision in which the total translational kinetic energy of the molecules is conserved.

Back 8

elastic collision

Front 9

kinetic energy (KE) = _(formula)____

Back 9

(1/2)mV²

Front 10

__________ is a collision in which the total translational kinetic energy of the molecules is conserved.

Back 10

elastic collision

Front 11

kinetic energy (KE) = _(formula)____

Back 11

(1/2)mV²

Front 12

True or False: A gas can be liquefied by pressure alone only if its temperature is at or below its critical temperature.

Back 12

True.

Front 13

True or False: A gas can be liquefied by pressure alone only if its temperature is at or above its critical temperature.

Back 13

False. A gas can be liquefied by pressure alone only if its temperature is at or BELOW its critical temperature.

Front 14

True or False: A gas can be liquefied by pressure alone only if its temperature is at or below its critical temperature.

Back 14

True.

Front 15

True or False: A gas can be liquefied by pressure alone only if its temperature is at or above its critical temperature.

Back 15

False. A gas can be liquefied by pressure alone only if its temperature is at or BELOW its critical temperature.

Front 16

How is the compression factor (Z) determined?

Back 16

Z = Vm / Vm{ideal}

Front 17

For Z > 1, are repulsive or attractive forces dominant?

Back 17

Repulsive forces are dominant. Z > 1 means the gas has a larger molar volume than a perfect gas ( a gas has to overcome attractive forces to accomplish this)

Front 18

For Z < 1, are repulsive or attractive forces dominant?

Back 18

Attractive forces. When Z < 1, volume is less than that of ideal gas. This is due to attractive forces between molecules.

Front 19

True or False: Z is usually greater than 1 at high pressures

Back 19

True.

Front 20

True or False: Z is usually greater than 1 at low pressures

Back 20

False. At low pressures, gases behave near perfectly, and Z is approximately = 1

Front 21

True or False: Z is usually less than 1 at intermediate pressures

Back 21

True.

Front 22

Z is usually less than 1 at _____________ pressure

Back 22

Intermediate

Front 23

How is the compression factor (Z) determined?

Back 23

Z = Vm / Vm{ideal}

Front 24

For Z > 1, are repulsive or attractive forces dominant?

Back 24

Repulsive forces are dominant. Z > 1 means the gas has a larger molar volume than a perfect gas ( a gas has to overcome attractive forces to accomplish this)

Front 25

For Z < 1, are repulsive or attractive forces dominant?

Back 25

Attractive forces. When Z < 1, volume is less than that of ideal gas. This is due to attractive forces between molecules.

Front 26

True or False: Z is usually greater than 1 at high pressures

Back 26

True.

Front 27

True or False: Z is usually greater than 1 at low pressures

Back 27

False. At low pressures, gases behave near perfectly, and Z is approximately = 1

Front 28

R = _______ (atm L)

Back 28

0.0821 atm L

Front 29

By convention, work done on a system by the surroundings is considered to be (positive or negative?)

Back 29

positive

Front 30

By convention, work done by a system on the surroundings is considered to be (positive or negative?)

Back 30

negative

Front 31

Formula for work (gases) =

Back 31

dW = -[external pressure] * [dV]

Front 32

1.0 L of gas freely expands to 2.0 L. How much work is done in L*atm?

Back 32

0. Freely expanding gases are a special case.

Front 33

A system in which both energy and matter come and go is known as __________

Back 33

open system

Front 34

A system in which only energy comes and goes into the surroundings is known as __________

Back 34

closed system

Front 35

The values a and b from the van der waals equation are specific to each _____, but independent of ______

Back 35

The values a and b from the van der waals equation are specific to each gas, but independent of temperature

Front 36

True or false: the values a and b from the van der waals equation do not change with temperature

Back 36

True

Front 37

True or false: the values a and b from the van der waals equation change with temperature

Back 37

False. They are different for every gas, but temperature does not change them.

Front 38

equation for potential energy (PE)

Back 38

PE = mgh (approx)
PE = K- (M1*M2)(1/___)
PE = K * (e^2/[radius between charges])

Front 39

Temperature is proportional to _________

Back 39

avg Kinetic energy

Front 40

Do ideal gases have potential energy?

Back 40

No

Front 41

Do real gases have potential energy?

Back 41

Yes

Front 42

What's another way of thinking of volume of a molecule?

Back 42

Repulsion (radius of molecule)

Front 43

Δ U = ______

Back 43

Δ internal energy (U) =work done on the system (W) + heat added to the system (Q) (1st law of thermodynamics - energy is conserved)

Front 44

KE = moving
PE = _________

Back 44

PE = interaction

Front 45

For ideal gas, energy (U) is proportional to ____________

Back 45

temperature (T)

Front 46

For a real gas, energy (U) is proportional to ____________

Back 46

temperature (T) and volume (V)

Front 47

How do you calculate work in terms of pressure and volume?

Back 47

dW = - p * dV

Front 48

Heat capacity (C) = ______

Back 48

Front 49

Heat capacity at constant volume = _______

Back 49

Cv = (dq)/(dT) = (dU)/(dT){sub} y

Front 50

Name the state functions

Back 50

volume, pressure, temp

Front 51

Name the path functions

Back 51

work, heat (q), and heat capacity (c)

Front 52

Why is heat capacity a path function?

Back 52

Because it can be arrived at through changes in temp OR changes in pressure

Front 53

What is a "reversible process"?

Back 53

One in which infinitesimal changes do not change the qualitative results

Front 54

What is an "irreversible process"?

Back 54

One in which infinitesimal changes change the qualitative results

Front 55

The __________ is the part of the world in which we have a special interest.

Back 55

system

Front 56

The ____________ comprise the region outside the system and are where we make our measurements.

Back 56

surroundings (also sometimes called "the environment")

Front 57

What's the difference between an "open" and "closed" system?

Back 57

Open systems are characterized by an exchange of matter and energy between system and surroundings. Closed systems are characterized by exchange of energy only.

Front 58

_______ is done to achieve motion against an opposing force.

Back 58

Work

Front 59

The ________ of a system is its capacity to do work.

Back 59

Energy

Front 60

A(n) ____________ process is a process that releases energy as heat into its surroundings.

Back 60

exothermic

Front 61

An ____________ process is a process in which energy is acquired from its surroundings as heat.

Back 61

endothermic

Front 62

A __________ change does not require work to bring it about

Back 62

spontaneous

Front 63

What is the second law of thermodynamics?

Back 63

The second law of thermodynamics is an expression of the tendency that over time, differences in temperature, pressure, and chemical potential equilibrate in an isolated physical system. (entropy is always increasing)

Front 64

For ideal gas, enthalpy (H) is a function of _________

Back 64

temperature

Front 65

For ideal gas, U is a function of __________

Back 65

temperature

Front 66

For a non-ideal gas, U is a function of ________

Back 66

potential energy times kinetic energy

Front 67

For non ideal gas, enthalpy (H) is a function of __________

Back 67

pressure (p) times temperature (T)

Front 68

Enthalpy (H) = ______

Back 68

H = U + pV

Front 69

Summarize the Joule-Thomson effect

Back 69

Kelvin–Joule effect describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment. This procedure is called a throttling process or Joule–Thomson process. At room temperature, all gases except hydrogen, helium and neon cool upon expansion by the Joule–Thomson process.

Front 70

What is the Joule-Thomson effect used for?

Back 70

gas liquification

Front 71

H_f - H_i = _______

Back 71

H_f -H_c + H_c - H_i

Front 72

What is kirchoff's law?

Back 72

ΔH{standard state} (T2) + ΔH{standard state} (298 K) + S (T2 - 298) + ΔC_p dT

Front 73

_________ is the transfer of energy that makes use of disorderly molecular motion

Back 73

Heating

Front 74

_________ is the transfer of energy that makes use of organized motion.

Back 74

work

Front 75

_________: the total energy of a system

Back 75

internal energy (U)

Front 76

True or False: Internal energy (U) is a state function

Back 76

True

Front 77

True or False: Internal energy (U) is a path function

Back 77

False: Internal energy (U) is a state function

Front 78

The _______ law states that the internal energy of an isolated system is constant.

Back 78

First law

Front 79

What is the First Law?

Back 79

The first law states that the internal energy of an isolated system is constant.

Front 80

Expansion work is proportional to the __________

Back 80

external pressure

Front 81

________ expansion does no work.

Back 81

free

Front 82

True or False: Free expansion does no work

Back 82

True

Front 83

True or False: Gas expansion does no work

Back 83

False: Free expansion [of gas] does no work

Front 84

True or False: The work of expansion against constant pressure is proportional to that pressure and to the change in volume

Back 84

True.

Front 85

True or False: The work of expansion against constant pressure is inversely proportional to that pressure and to the change in volume

Back 85

False: The work of expansion against constant pressure is PROPORTIONAL to that pressure and to the change in volume

Front 86

To achieve reversible expansion, the ____________ is matched at every stage to the pressure of the system.

Back 86

external pressure

Front 87

The work of reversible, isothermal expansion of a perfect gas is a ________ function of the volume.

Back 87

logarithmic

Front 88

The work of reversible, isothermal expansion of a perfect gas is a logarithmic function of the _________.

Back 88

volume

Front 89

The work of _________ expansion of a perfect gas is a logarithmic function of the volume.

Back 89

reversible, isothermal

Front 90

Energy transferred as heat at constant pressure is equal to the change in ________ of a system.

Back 90

enthalpy

Front 91

Enthalpy changes are measured in a___________

Back 91

constant-pressure calorimeter

Front 92

The heat capacity (C) at constant pressure is equal to the slope of ___________.

Back 92

enthalpy with temperature

Front 93

For the reversible adiabatic expansion of a perfect gas, pressure, and volume are related by an expression that depends on the ratio of ___________

Back 93

heat capacities

Front 94

The standard enthalpy of transition is equal to the energy transferred as_______ at constant pressure in the transition.

Back 94

heat

Front 95

The _________ is equal to the energy transferred as heat at constant pressure in the transition.

Back 95

standard enthalpy of transition

Front 96

A ___________ is a chemical equation and its associated change in enthalpy.

Back 96

thermochemical equation

Front 97

_________ states that the standard enthalpy of an overall reaction is the sum of the standard enthalpies of the individual reactions into which a reaction may be divided.

Back 97

Hess's law

Front 98

The _________ of a substance at a specified temperature is its pure form at 1 bar.

Back 98

standard state

Front 99

Standard enthalpies of formation are defined in terms of the reference states of ________

Back 99

elements

Front 100

The standard reaction enthalpy is expressed as the ___________ of products and reactants

Back 100

difference of the standard enthalpies of formation

Front 101

The temperature dependence of a reaction enthalpy is expressed by ___________

Back 101

Kirchhoff's law

Front 102

What is Kirchhoff's equation?

Back 102

Front 103

The __________ is the change in temperature of a gas when it undergoes isenthalpic expansion.

Back 103

Joule-Thomson effect

Front 104

What important observation did Clausius make?

Back 104

Heat (q) always flows from higher temperature (T) to lower temperature (T)

Front 105

in terms of entropy (S), dS = ____

Back 105

dS = (dq_rev) / T

Front 106

What is the equation for engine efficiency?

Back 106

n = (w/q_h) ≤ (T_h -T_c) / T_h

Front 107

For ideal gas, C_pm - C_vm = ____

Back 107

R (a constant)

Front 108

What do you need to remember about calculating entropy of substances above the melting point or boiling point?

Back 108

You must add the entropy from the "same phase" equation to the entropy from the "phase change" equation.

Front 109

For any engine, ⱨ = ____

Back 109

ⱨ = (w/Q_h) = (T_h - T_c) / T_h

Front 110

To which condition does the Clausius Inequality apply?

Back 110

A small system and infinitely large surroundings

Front 111

dS_tot = dS_sys - (dq_sys / __?__) ≥ 0

Back 111

dS_tot = dS_sys - (dq_sys / T_surr) ≥ 0

Front 112

___ = internal energy(U) - temperature(T) * entropy(S)

Back 112

A (Helmholtz energy equation)

Front 113

___ = enthalpy(H) - temperature(T) * entropy(S)

Back 113

G (Gibbs free energy)

Front 114

Under constant volume(V), what is the relationship between dq and dU?

Back 114

du = dq

Front 115

Under constant pressure(p), what is the relationship between dq and dH?

Back 115

dq = dH

Front 116

dA (less than, equal to, greater than?) 0

Back 116

dA_(V,T) ≤ 0

Front 117

dG (less than, equal to, greater than?) 0

Back 117

dG_p,T ≤ 0

Front 118

Let's say you calculate ∆G for a rxn. It is -474. Is this reaction spontaneous?

Back 118

Yes. Any ∆G less than zero is spontaneous. (i.e. Gibbs energy decreases during spontaneous reactions)

Front 119

True or False: dU = C_v dT

Back 119

True

Front 120

As long as you see "adiabatic process", q = ____

Back 120

q = 0

Front 121

For a one component system, ∆μ = ___

Back 121

∆μ = ∆G

Front 122

dG = ___

Back 122

-S dT + Vdp

Front 123

For constant pressure, what is dG/dT =_____?

Back 123

- S

Front 124

chemical potential is also known as ________

Back 124

molar Gibbs energy (G_m)

Front 125

For liquids and solids, _______ can be assumed to be constant.

Back 125

volume

Front 126

μ-μ^o = _______

Back 126

μ-μ^o = RT ln (p/p^o)

Front 127

At pressure below vapor pressure, which has a lower Gibbs energy, gas or liquid?

Back 127

gas

Front 128

At pressure above vapor pressure, which has a lower Gibbs energy, gas or liquid?

Back 128

liquid

Front 129

At pressure below vapor pressure, which has a higher Gibbs energy, gas or liquid?

Back 129

liquid

Front 130

At pressure above vapor pressure, which has a higher Gibbs energy, gas or liquid?

Back 130

gas

Front 131

Describe the features of a typical "phase diagram"

Back 131

(incomplete)

Front 132

μ is always same for different _______ when at equilibrium

Back 132

μ is always same for different phases when at equilibrium

Front 133

What is abnormal about a water phase diagram?

Back 133

The line that distinguishes solid from liquid has a negative slope, indicating that as pressure increases, melting point decreases.

Front 134

C_(v,m) = C_(p,m) - ____

Back 134

R (0.821 atm L^-1) or (8.314 Pa m^-1)

Front 135

Gibbs phase rule: __________

Back 135

Freedoms (F) = chemical components (C) - number of phases (P) + 2

Front 136

Describe the graph of chemical potential (μ) VS. temperature (T)

Back 136

The line for solid phase occupies the lowest T and highest μ. It has a negative slope. Liquid has a steeper negative slope. Gas has an even steeper negative slope. Gas occupies the highest temperatures and lowest μ.

Front 137

What is the fundamental equation for dμ?

Back 137

dμ = V_m * dP - S_m * dT