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ChE LE Flashcards > Physical Chemistry and Material Science > Flashcards

Physical Chemistry and Material Science Flashcards

1
Q

System that allows exchange of both matter and energy

A

Open System

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2
Q

System that allows exchange of energy and not matter

A

Closed System

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3
Q

System that does not allow exchange of both matter and energy

A

Isolated System

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4
Q

PV=k

A

Boyle’s Law or Mariotte’s Law

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5
Q

V/T=k

A

Charles’ Law

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6
Q

P/T=k

A

Gay-Lussac’s law

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7
Q

Achieved at high temperature and low pressure

A

Ideal Gases

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8
Q

Where intermolecular forces (IMFA) are significant

A

Real Gases

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9
Q

What is the significance of Modified Equations of State?

A

accounts for pressure and volume changes due to IMFA

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10
Q

For a real gas, what causes the deviation from the ideal pressure at a molecular level?

A

Intermolecular forces of attraction of the molecules with one another

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11
Q

When gas molecules collide, they experience _____ collision.

A

Perfectly elastic

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12
Q

0th Law of Thermodynamics
(Proponent, Definition)

A

Ralph Howard Fowler
If TA=TB and TB=TC, then TA=TC

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13
Q

1st Law of Thermodynamics
(Proponent, Definition)

A

Rudolf Julius Emanuel Clausius
-Law of Conservation of Energy
-Energy can’t be created/destroyed, only transformed
-Energy of universe is constant
-The total energy of any system and its surroundings is conserved.

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14
Q

2nd Law of Thermo (Clausius Statement)
(Proponent, Definition)

A

A device that solely transfers heat from low to high temperature is impossible. Work is required.

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15
Q

2nd Law of Thermo (Kelvin-Planck Statement)

A

A) Impossible for device to completely convert heat to work (n < 1, and n < n,Carnot), effect to surroundings always exist.

B) Impossible for any device operating on a cycle to receive heat from a SINGLE RESERVOIR ONLY and produce a net amount of work. A hot and cold reservoir are required.

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16
Q

3rd Law of Thermodynamics

A

Walther Hermann Nernst
- S=0 at absolute zero (especially perfect crystals), then S>0 for everything else

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17
Q

Carnot Theorem

A

Nicolas Sadi Carnot
-n,Carnot = n,max (No engine is more efficient than Carnot engine)
- Any reversible engine between two heat reservoirs is a Carnot Engine

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18
Q

For Carnot engines:
Its efficiency depends only on _____ and not the working substance of the engine.

A

temperature levels (Tc and Th)

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19
Q

Which of the following is not conserved in any process?
a. Mass
b. Energy
c. Momentum
d. Entropy

A

Entropy

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20
Q

Increasing the temperature of the cold reservoir _____ the Carnot efficiency

A

Decreases

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21
Q

If the entropy of a system decreases, the entropy of its surroundings

A

Must always increase
(Since dS,univ > 0)

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22
Q

Defines entropy in terms of the number of ways that the molecules can be arranged amongst the energy states, subject to the arrangements having the same overall energy.

A

Boltzmann formula

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23
Q

What does Clausius Inequality say?

A
  • Entropy increases for spontaneous processes
  • dS > 0 indicated spontaneity
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24
Q

What does Nernst Heat Theorem say?

A

Related to Third Law
Entropy change approaches zero as the temperature approaches zero:
* ΔS → 0 as T → 0
* Provided all substances are perfectly ordered.

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25
Q

Conditions wherein the difference between gas and liquid starts to disappear

A

Critical Parameters

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26
Q

Father of Thermochemistry

A

Germain Henri Hess

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27
Q

The amount of heat absorbed when CO2 gas reacts with a solid CaO to form solid CaCO3 is measured in a bomb calorimeter. The data obtained give a direct measure of:

A

ΔU

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28
Q

AKA Constant Volume Calorimeter

A

Bomb Calorimeter

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29
Q

AKA Constant Pressure Calorimeter

A

Adiabatic Flame Calorimeter

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30
Q

The energy required to completely separate one mole of a solid ionic compound into gaseous ions

A

Lattice energy

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31
Q

The equilibrium intensive state of a system is described by specifying the temperature, pressure, and:

A

Mole fractions

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32
Q

Determine whether the changes in entropy (ΔS) and enthalpy (ΔH) are positive, negative, or near zero.
1. Ethyl alcohol evaporating from glass container
2. A diatomic molecule dissociates into atoms
3. Charcoal is burned to form CO2
and water

A
  1. ΔH>0, ΔS>0;
  2. ΔH>0, ΔS>0;
  3. ΔH>0, ΔS>0
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33
Q

It is the property of a fluid that is caused by shearing effect of a fluid layer moving past another layer.

A

Viscosity

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34
Q

Is Van der Waals EoS independent of critical parameters?

A

No

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35
Q

State the Principle of Corresponding States

A

Substances with equal Pr, Tr and Vr have the same properties

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36
Q

Temperature at which property of real gas becomes ideal

A

Boyle Temperature

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37
Q

The tendency of gas to flee or escape

A

Fugacity Coefficient

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38
Q

Gas behavior if fugacity coef is:
*>1
*=1
*<1

A

*>1: Repulsive
*=1: Ideal
*<1: Attractive

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39
Q

Indicates a temperature change upon isenthalpic gas expansion

A

Joule-Thomson Coefficient

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40
Q

Most gases cools down during isenthalpic processes except __

A

Hydrogen and helium

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41
Q

Temperature at which Joule-Thomson Coefficient shifts sign

A

Inversion Temperature

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42
Q

Gas behavior if Joule-Thomson Coefficient is:
*>0
*=0
*<0

A

*>0: Attractive
*=0: Ideal
*<0: Repulsive

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43
Q

Most compact physical state having the strongest interaction between particles

A

Solids

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44
Q

Solids with fixed geometric pattern and melting points

A

Crystalline solids

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45
Q

Solids with irregular geometric pattern and melting points.

A

Amorphous solids

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46
Q

Differentiate Types of Solids (based on composition, melt point, thermal and electric conductivity):
Ionic
Molecular
Polymeric
Network Covalent
Metallic
Amorphous

A

Ionic: crystals made of ions (NaCl salt)
High melt pt, low electric and thermal conductivity

Molecular: crystals made of molecules (ice)
Low melt pt, low electric and thermal conductivity

Polymeric: giant molecules; may be crystalline, amorphous or semicrystalline (rubber, plastics, proteins), low electric and thermal conductivity

Network Covalent: large number of covalent bonds (diamond and quartz)
High melt pt, low electric and thermal conductivity

Metallic: held together by metallic bonds (gold)
Varying melt pt, high electric and thermal conductivity

Amorphous: randomly arranged molecules. No melting point (soot, tar, glass)

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47
Q

Solids characterized by an array of positive ions immersed in a sea of valance electrons

A

Metallic

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48
Q

Solids that lack a regular three-dimensional arrangement of atoms

A

Amorphous Solids

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49
Q

Solids joined by van der Waals, hydrogen bonds or Dipole-dipoles

A

Molecular Solids

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50
Q

Solids that cannot be melted

A

Covalent Solids

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51
Q

Reason for good electric and thermal conductivity of Metallic solids

A

mobility of the delocalized electrons

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52
Q

The best electrical conductor

A

Silver

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53
Q

Other term for Solidification

A

Crystallization

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54
Q

Optically transparent fusion product of inorganic materials that has cooled to a rigid state without crystallizing

A

Glass

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55
Q

Common form of elemental Carbon

A
  1. Diamond
  2. Graphite
  3. Buckyballs
  4. Nanotubes
  5. Soot
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56
Q

The only Network Covalent solid with good thermal conductivity

A

Diamond

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57
Q

Covalent solid with good electric conductivity

A

Graphite

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58
Q

Types of Crystal Lattice

A

Simple Cubic
-# atoms: 1
-Coordination Number: 6
-Packing Efficiency: 52%

Body Centered Cubic
-# atoms: 2
-Coordination Number: 8
-Packing Efficiency: 68%

Face-Centered Cubic
-# atoms: 4
-Coordination Number: 12
-Packing Efficiency: 74%

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59
Q

Branch of chemistry that qualitatively and quantitatively describes the energy changes that occur during chemical reactions

A

Thermochemistry

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60
Q

Reactions that take place in a single phase (i.e., liquid, gas, or solid)

A

homogeneous reactions

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61
Q

Reactions that occur at surfaces between phases

A

heterogeneous reactions

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62
Q

When does a crystal get hydrated?

A

When H2O becomes an integral part of the crystal lattice

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63
Q

Property most often used as measure of thermodynamic potential

A

Gibbs Free Energy

64
Q

Basis of Phase Diagrams of single component systems

A

Clapeyron Equation
dP/dT = dS/dV,m

65
Q

Describe Trouton’s Rule

A

Molar entropies of vaporization of all substances are equal IF IMFA is not significant

dS,vap = 88 J/mol*K (nasa HB)

66
Q

Trouton’s rule fails for ___ hence it is frequently used for ___

A

Highly polar liquids
frequently used for Hydrocarbons

67
Q

The unit-lateral deformation of a body under stress divided by the unit longitudinal deformation is known as

A

Poisson’s ratio

68
Q

The ability of a solid substance to resist abrasion and surface deformation.

A

hardness

69
Q

The measure of a material’s resistance to localized plastic deformation.

A

hardness

70
Q

The maximum stress that can be sustained by a structure in tension

A

tensile strength

71
Q

The capacity of a material to absorb energy when it is deformed elastically and then, upon unloading, to have this energy recovered.

A

resilience

72
Q

The property that is indicative of a material’s resistance to fracture when a crack is present.

A

toughness

73
Q

What is the ability to return to the original shape after being deformed called?

A

elasticity

74
Q

It is the ability to be shaped

A

malleability

75
Q

It is a measure of the degree of plastic deformation that has been sustained at fracture.

A

ductility

76
Q

A material that experiences very little or no plastic deformation upon fracture

A

brittle

77
Q

What does the Clapeyron Equation tell us?

A

T and P change to keep their chemical potentials equal

78
Q

Assumption in Clapeyron Equation

A

Molar volume of liquid negligible
Vapor obeys ideal gas laws

79
Q

Describe Gibbs Phase Rule

A

F = 2 + C - P - R
*Used to determine degrees of freedom of a system.
*number of intensive variables required to describe and entire system

80
Q

What does the Gibbs-Duhem equation calculate?

A

G = uAnA + uBnB + ……
Gibbs-Duhem equation relates COMPOSITION in liquid phase and the:
-fugacity
-partial pressure
-activity co-efficient
at constant temperature & pressure.

81
Q

For miscible systems, the boiling point of the solution is

A

Between the boiling points of the two liquids

82
Q

Describe colligative property

A

Property that depend on the quantity of solutes and nature of solvents, and NOT the nature of solutes

83
Q

When BPE and FPD happens?

A

BPE - at high T, solute causes increased IMFA hence higher energy required to boil

FPD - at low T, solute causes decreased IMFA hence solvent freezes at lower T

84
Q

Determination of Molecular Mass via:
1. Freezing pt
2. Boiling pt
3. Osmotic pressure

A
  1. Freezing pt:
    Cryoscopy
  2. Boiling pt:
    Ebullioscopy
  3. Osmotic pressure:
    Osmometry
85
Q

In colligative props, presence of solute causes ____

A
  1. decrease in chemical potential
  2. increase in entropy
86
Q

In osmosis, at equilibrium, chemical potential of the pure solvent side should be _____ chemical potential of the side with solute.

A

equal to

87
Q

Rank in terms of vapor pressure lowering and ions made?
a. sucrose, C12H22O11
b. Aluminum chloride, AlCl3
c. Table salt, NaCl
d. Sodium sulfate, Na2SO4

A

a. sucrose, i=1
b. AlCl3, i=4
c. NaCl, i=2
d. Na2SO4, i=2

88
Q

Which of the following is not conserved in any
process?
a. Mass
b. Energy
c. Momentum
d. Entropy

A

Entropy

89
Q

The equilibrium intensive state of a system is described by specifying the temperature, pressure, and _____

A

Mole fractions

90
Q

____ is a state function that determines whether a physical change or chemical reaction can occur simultaneously in a closed system

A

entropy
(spontaneously dapat)

91
Q

Describe Gibbs-Duhem Theorem

A

Describes relationship between chemical potential of a system and its composition while maintaining equilibrium

92
Q

Differentiate Henry’s Law and Raoult’s Law
Define Ideal Solution and Non-ideal Solutions

A
  • Raoult’s Law (Pa=x*Pt) for ideal solutions
  • Henry’s Law (Pa=H*xa) for non-ideal dilute solutions
  • Ideal solution: negligible molecule size difference and intermolecular interactions.
  • Non-Ideal solution: heightened interactions
93
Q

Henry’s law states that ____

A

Pa = H*xa
At constant temperature, amount of gas dissolved in liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

94
Q

Differentiate Positive and Negative Deviating Systems (Henry’s Law) in terms of:

A

Positively-Deviating System
*Vapor pressure: > P,ideal
*Polarity: Different (polar and nonpolar)
* Behavior: Endothermic Expansion
*Example: Ethanol-Hexane

Negatively-Deviating System
*Vapor pressure: < P,ideal
*Polarity: Similar (both polar/ nonpolar)
* Behavior: Exothermic Contraction
* Example: Acetone-water

95
Q

Maximum amount of the solid that will dissolve in a given amount of a particular solvent at a given temperature.

A

Solubility

96
Q

Explain “like dissolved like”

A

polar dissolved polar
nonpolar dissolved nonpolar

97
Q

Effect on temperature on solubility of solids, liquid and gasses in liquid

A

Increased solid and liquid solubility
Decrease gas solubility

98
Q

Define Colloids (and physical characteristics)

A

Dispersion of NANOSCALE (1nm to 1000nm) particles throughout the continuous phase.
* scatter light (Tyndall effect)
* form stable dispersions not easily settleable

99
Q

Way to crystallize the excess solute is to add a crystal of the solute

A

seeding

100
Q

Happens when elevated temperature affects aquatic life. What do we call this phenomena?

A

thermal pollution

101
Q

Effect on PRESSURE on solubility of solids, liquid and gasses in liquid

A

Negligible increase in solid and liquid solubility
Substantial increase gas solubility (carbonated softdrinks)

102
Q

Why a bottle of beer or a carbonated beverage foams when it is opened?

A

Henry’s Law: Pa=Pa,sat*xa
Lower external pressure Pa, Lower solubility of gas

103
Q

Differentiate Solutions, Colloids and Suspension

A

Colloids: nanoscale size particles (1nm to 1000nm)
Solutions: smaller than nano
Suspensions: larger than nano. Separates in standing

104
Q

The scattering of light by colloidal-size particles

A

Tyndall effect

105
Q

Liquid droplets or solid particles dispersed throughout a gas

A

aerosols

106
Q

Liquid droplets dispersed throughout another liquid.

A

emulsion

107
Q

Solid particles dispersed in a liquid.

A

sol

108
Q

Colloidal-sized particle formed in water by the association of molecules or ions that each have a hydrophobic end and a hydrophilic end.

A

micelle

109
Q

Solution wherein no additional solute can be dissolved

A

Saturated solution

110
Q

Solution wherein additional solute can still be dissolved

A

Undersaturated solution

111
Q

Heat change that results when 1 mole of the compound is formed from its elements at a pressure of 1 atm.

A

Standard heat of formation

112
Q

What is the standard heat of formation of elements in their most stable form? Why?

A
  • zero
  • used as reference point such that Standard heat of formation of COMPOUNDS is the summation of heats from its elements.
113
Q

Explain Hess’s law

A

“When reactants are converted to products, the change in enthalpy is the same whether the
reaction takes place in one step or in a series of steps.”
* Enthalpy involved in a process can be broken down into steps
* dH = sum(vH,p) - sum(vH,r)

114
Q

Direct Method to determine Heat of Reaction

A

*If substance easily formed
e.g. C (graphite) + O2 –> CO2

115
Q

change from a gas to a liquid

A

Condensation

116
Q

change from a liquid to a solid

A

solidification

117
Q

Why enthalpy of formation for an element in its elemental state or naturally occurring state is always equal to ZERO?

A
  • Naturally occuring = most stable
  • It takes no energy to form a naturally occurring compound.
118
Q

Why is it when diluting, the acid is added to water and not the other way around?

A

Heat of Dilution
- Dilution of acid with water is highly exothermic. The more water is added to acid, the more heat it releases to surroundings causing it to boil.

119
Q

Explain Excess properties

A

M,xss = M,actual - M,ideal
Difference between the actual property solution and its value if it were to be an ideal solution at the same T and P and composition is called

120
Q

Describe Helmholtz Free Energy
(Proponent, Equation, Definition)

A
  • Hermann Ludwig Ferdinand von Helmholtz
  • A=U-TS
  • Maximum work by system at T=k
  • The energy that can be transformed into uniform motion (U is total energy, TS is disordered motion, their difference is uniform motion)
121
Q

Describe Gibbs Free Energy
(Proponent, Equation, Definition)

A

Josiah Willard Gibbs
G=H-TS
Maximum (non-expansion) work by system at P&T=k
Frequently used to determine system’s chemical potential (chem pot = G/n)

122
Q

Criteria for Equilibrium for:
Entropy
Gibbs Free Energy
Helmholtz Free Energy

A

LAHAT dS = dG,T,P = dA,T,V = 0

123
Q

Criteria for Spontaneity for:
Entropy
Gibbs Free Energy
Helmholtz Free Energy

A

For Gibbs and Helmholt: dG < 0 & dA < 0
For Entropy: dS > 0

124
Q

What does Clapeyron calculate?

A

slope of a phase boundary.

125
Q

Basis for phase diagrams

A

Clapeyron equation

126
Q

What does Clausius Clapeyron equation calculate?

A

Boundary between a liquid phase and its vapor phase.

127
Q

Describe Azeotropes and their Boiling points

A
  • When liquid-vapor system, with constant boiling point because their liquid and vapor composition is equal
  • Hard to distill, requires additional mass transfer agent
  • Boiling point between the more and less volatile component
128
Q

Pick out the system with maximum boiling azeotrope at 1 atm.
A. Acetone chloroform
B. Ethyl alcohol-water
C. Benzene-ethyl alcohol
D. None of these

A

Acetone chloroform

129
Q

Pick out the system with minimum boiling azeotrope at 1 atm.
A. Benzene-toluene
B. Ethyl alcohol-water
C. Hydrochloric acid-water
D. All of the above

A

Ethyl alcohol-water

130
Q

A minimum boiling azeotrope is exemplified by
A. Toluene-benzene
B. Acetone-carbon disulphide
C. Water-isobutyl alcohol
D. None of these

A

Acetone-carbon disulphide

131
Q

Which of the following binary systems is an example of a maximum boiling azeotrope?
A. Water-hydrochloric acid
B. Acetone-carbon disulphide
C. Water-ethyl alcohol
D. N-heptane-n-octane

A

Water-hydrochloric acid

132
Q

With increase in temperature, the solubility of gases in liquids, at fixed pressure ___

A

Decreases

133
Q

__________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid.

A

Dew point

134
Q

Branch of chemistry that deals with the interconversion of electrical energy and chemical energy

A

Electrochemistry

135
Q

Experimental apparatus for generating electricity through the use of a spontaneous reaction

A

galvanic cell or voltaic cell

136
Q

Electrode in galvanic cell at which oxidation and reduction occurs, RESPECTIVELY

A

RedCath, AnOx
Anode: Oxidation
Cathode: Reduction

137
Q

Conducting medium through which the cations and anions can move from one electrode compartment to the other.

A

salt bridge

138
Q

What happens without the salt bridge?

A

There will be buildup of positive charge in anode compartment, and negative on cathode compartment.
PREVENTS GALVANIC CELL FROM WORKING

139
Q

The voltage across the electrodes of a galvanic cell

A

Cell potential or Electromotive force (emf)

140
Q

Voltage associated with a reduction reaction at an electrode when all solutes are 1M and all gases are at 1 atm

A

standard reduction potential

141
Q

The more negative the standard electrode potential is, the more likely the reaction is to proceed from ___ to ___

A

right to left
Recall: negative E and positive dG is nonspontaneous

142
Q

The more positive the standard reduction potential, the greater the electrode’s tendency to be _____ and the higher its strength as an _____ agent

A

the greater the electrode’s tendency to be REDUCED and the higher its strength as an OXIDIZING AGENT

143
Q

Strongest oxidizing agent

A

F2
Has highest reduction potential

144
Q

Weakest oxidizing agent

A

Li+
Has lowest reduction potential

145
Q

Why does changing the stoichiometric coefficients of a half-cell reaction does not affect the value of standard reduction potentials?

A

Because electrode potentials are intensive properties

146
Q

Weakest oxidizing agent

A

Li+
Has lowest reduction potential

147
Q

Maximum work a cell can achieve

A

Equal to electromotive force and Gibbs free energy
w,max = dG = w,ele = -nFE,cell

148
Q

Quantity of electricity carried by 1 mole of electrons

A

Faraday’s constant
96,500 C / mole e-

149
Q

Gives the relationship between the cell emf and the concentrations of the reactants and products under non-standard-state conditions.

A

Nernst equation

150
Q

If the entropy of a system decreases, the entropy of its surroundings ____

A

Must always increase

151
Q

For a particular chemical reaction, ΔH˚ is positive and ΔS˚ is negative. Which of the ff statements is TRUE?
A. The reaction will be spontaneous only if the magnitude of ΔH˚ is large enough to cover the unfavorable entropy change.
B. The reaction will be spontaneous only if the magnitude of ΔS˚ is large enough to overcome the unfavorable enthalpy change.
C. The reaction will be spontaneous regardless of the magnitudes of ΔH˚ and ΔS˚.
D. The reaction cannot be spontaneous.

A

dG=dH-TdS
D. The reaction cannot be spontaneous.

152
Q

In which of the following cases does entropy decreases?
A: Polymerization of Styrene and Butyl Acrylate
B: Dissolving Mohr’s salt in water
C: Expansion of high purity hydrogen gas
D: Melting silver ingots

A

A: Polymerization of Styrene and Butyl Acrylate

153
Q

When steam condenses into water at 90 deg C, the entropy of the system decreases. Which of ff is true?
A: Entropy of the universe also decreases
B: Entropy of the surrounding increases to the same extent to which entropy of the system decreases
C: Entropy of the surrounding also decreases
D: Entropy of the surrounding increases to a greater extent than the decrease in the entropy of the system

A

D: Entropy of the surrounding increases to a greater extent than the decrease in the entropy of the system

154
Q

For the following process occurring at 100 deg C and 1 atm:
H2O (l) —–> H2O (g)
Which among the following statements is correct?
A: delta S_system > 0 & delta S_surrounding > 0
B: delta S_system < 0 & delta S_surrounding > 0
C: delta S_system < 0 & delta S_surrounding < 0
D: delta S_system > 0 & delta S_surrounding < 0

A

D: delta S_system > 0 & delta S_surrounding < 0

155
Q

Common formes of elemental Carbon

A
  1. Diamond
  2. Graphite
  3. Buckyballs
  4. Nanotubes
  5. Soot

ChE LE Flashcards (20 decks)

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