CHE317 Final Vocabulary

What is the Zeroth Law of Thermodynamics?

if system A is in thermal equilibrium with system B and system B is in thermal equilibrium with system C, then system A is in thermal equilibrium with system C

What is the 'written' definition for the First Law of Thermodynamics?

energy may not be greater nor destroyed, only transferred or changes from one form to another

What is the mathematical definition of the First Law of Thermodynamics?

∆U = q + w, where U is a state function

What is the 'written' definition of the Second Law of Thermodynamics as proposed by Carnot?

one cannot convert heat into work in a cyclic process without losing some heat to a low temperature reservoir

What are two mathematical definitions of the Second Law of Thermodynamics?

(dS)↓U,V >/= 0; (dA)↓T,V

What is the Third Law of Thermodynamics?

the entropy of all pure perfect crystalline substances is zero at zero kelvin

van der waals equation

P = (nRT/V-nb)-(n^2a/V^2) = (RT/Vm-b)-(a/Vm^2)

Redlich-Kwong Equation

P = (nRT/V-nB)-(n^2a/V(√T)(V+nB)) = (RT/Vm-B)-(A/Vm(√T)(Vm+B)

Boyle Temperature

temperature at which a gas behaves most ideally

equation fo boyle temperature

Tb = (a/bR)

state function

any property that can be determined by thermodynamic properties alone

intensive properties

thermodynamic properties that are not affected by the size of the system

extensive properties

thermodynamic properties that are affected by the size of the system

open system

energy and matter can be transferred from system to surroundings and vice versa

closed system

energy, but not matter, may be transferred

isolated system

neither energy nor matter may be transferred

adiabatic process

process that occurs in an isolated system, no conduction or transmission of heat

reversible process

a process that may be reversed at any moment by changing an independent variable by an infinitesimal amount

internal energy

delta U

internal energy

a state function, the sum of heat and work

thermodynamic efficiency

(of a carnot engine) is the ratio of the net work obtained (-w) to the fuel burned to provide heat (qz)

mathematical equation for enthalpy

H=U + PV

enthalpy

delta H

enthalpy

total heat content of a system, equal to the internal energy of the system plus the product of pressure and volume

Debye's T^3 Law of Heat Capacity

Cp(T) --> T³ as T-->0

Entropy mathematically defined

dS = (dqrev/T)

entropy

the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work

Gibbs Free Energy (mathematical equation)

G=H-TS

Helmholtz Free Energy (mathematical equation)

A=U-TS

Cpm/Cvm for an Ideal monatomic gas

Cvm = 3/2R, Cpm = 5/2R

Cpm/Cvm for an ideal diatomic gas

Cvm = 5/2R, Cpm = 7/2R

Activity

a=e^(µ-µ⁰/RT)

chemical potential

molar free energy

triple point

when all three phases are in equilibrium at a particular point

Gibbs-Helmholtz Equation

δ/δT(∆G/T)p = (-∆H/T²)

Clapeyron Equation

(dP/dT) = (∆Hm/T∆Vm)

Clausius-Clapeyron Equation

ln(P2/P1) = (-∆vapH/R)(1/T2-1/T1)

Van't Hoff Equation

ln(K2/K1)=(-∆rxnH°/R)(1/T2-1/T1)

joule-thomson coefficient

the derivative of the temperature with respect to the pressure at constant enthalpy

joule-thompson inversion temperature

the temperature at which uj-t = 0

critical temperature

the temperature, for a gas, above which it is impossible to liquify, regardless of pressure

law of corresponding states

the assumption that different gases have the same equation of state if each gas is described by reduced variables

Henry's Law

the vapor pressure of component A as Xa --> 0 is linear in Xa but the slope is not equal to Pa*

minimum boiling azeotropes

solutions which exhibit positive deviations from Raoult's Law

maximum boiling azetropes

solutions which exhibit negative deviations from Raoult's Law

law of mass action

the rates of chemical reactions = active masses of reacting species

molecularity

the sum of exponents in the rate law; tells how many species are coming together at the critical time in the reaction

half-life

the amount of time required for half of the initial concentration of the reactant to react

catalyst

a species that speeds up a reaction, without being consumed itself, by lowering the activation energy

transition state

chemical species found at the top of the activation barrier. it is an energy maximum in the direction of the reaction pathway, but an energy minimum in all other dimensions

activation energy

Ea

reaction intermediate

chemical species which lies somewhere along the reaction pathway and is a local energy minimum. However, such a species may or may not be able to isolated depending on the depth of its energy well

steady state approximation (mathematically)

(d[I]/dt) = 0

steady state approximation

the concentration of the intermediate does not appreciably change with time

Arrhenius Equation

lnK = lnA-(Ea/RT) or K = Ae^(-Ea/RT)

zeroth order reaction

half-life is direction proportional to initial concentration
concentration versus time is linear

Integrated Rate Law of Zeroth Order Reactions

[A] = -akt + [A₀]

Half-Life of Zeroth Order Reactions

t1/2 = [A₀]/2ak

first order reaction

natural log of concentration versus time is linear
half life is constant

Integrated Rate Law of First Order Reactions

ln[A] = -akt + ln[A₀]

Half life reaction of first order reactions

t1/2 = ln2/ak

second order reaction

reciprocal concentration versus time is linear
half life doubles

Integrated Rate Law of Second Order Reactions

1/[A] = akt + 1/[A₀]

half life reaction of second order reactions

t1/2 = 1/ak[A₀]

william thomson

lord kelvin

william thomson

rediscovered Carnot's work, corrected it to conform with the first law of thermodynamics

rudolf clausius

worked with Thomson to correct Carnot's work to conform with the first law of thermodynamics

Sadi Carnot

french engineer who most likely would have discovered the first and second laws of thermodynamics had he not died of cholera at age 36

James Prescott Joule

proved heat is a method by which system exchange energy, showed that the same change in state (a certain rise in temperature) can be accomplished either by doing work on a body or heating it

Peter Debye

a Dutch chemist who was the first to show that for non-metallic solids, Cp(T) --> T3 as T-->0, this T3 temperature dependence has been shown to be valid experimentally

max planck

first postulated the third law of thermodynamics

walther nernst

first postulated that the entropy of any reaction approaches zero as the temperature approaches 0 Kelvin

Raoult's Law

Pi = XiPi*

fugacity
-for an ideal gas
-for a real gas

a = P/Po, a = f/Po

Trouton's Rule

states that the entropy of vaporization is almost the same value, about 85-88J, for various kinds of liquids at their boiling point

Le Chatelier's Principle
1. increase [A] shifts...
2. decrease [A] shifts...
3. increase pressure shifts...
4. decrease pressure shifts...
5. increase temperature shifts...
6. decrease temperature shifts...

1. to products
2. to reactants
3. to side with fewer molecules
4. to side with more molecules
5. to side with more molecules
6. to side with fewer molecules

Reduced Temperature

Tr = T/Tc

Reduced Pressure

Pr = P/Pc

Reduced Molar Volume

Vr = V/Vc

Hess's Law

path independence means that the enthalpy change for any sequence of reactions that sum to the same overall reaction is identical

van der waals constant a

addresses the intermolecular forces the coefficient of thermal expansion related to the attractive forces between molecule Constant in that takes into account the attractive forces for a pure substance

van der waals constant b

addresses the actual volume of the gas particles related to the repulsive forces between molecules A constant that takes into account the repulsive forces for a pure substance, minimum

joule expansion

two moles of an ideal monatomic gas expand adiabatically into an evacuated container (vacuum), tripling the original volume this type of expansion is a

swamping

using the excess of everything except one reactant

Svante Arrhenius

Swedish chemist who proposed molecular definitions of acids and bases

isothermal process

thermodynamic process in which the temperature of the system remains constant

isobaric process

a process occurring at constant pressure

isochloric process

thermodynamic process taking place at constant volume

temperature

intensive property
state function
a measure of the average kinetic energy of the particles that make up a substance

heat (q)

energy transferred due to a temperature difference
extensive property
not a state function
the energy of the random motion of the particles that make up a substance

work (dw)

the energy transferred by virtue of a mechanical link between systems
dw=-PdV
for a compression, reversible work (on system) is minimum work
for an expansion, reversible work (by system) is maximum work

internal pressure

the rate at which the internal energy changes with volume at constant temperature

Joule-Thomson expansion

a method of expansion in which a gas or liquid at pressure P1, without a considerable change in kinetic energy, flows into a region of lower pressure P2

dew point curve

the temperature at which the vapor starts to condense

bubble point curve

the temperature at which the liquid starts to vaporize

Sir James Dewar

British chemist and physicist known for his invention of the vacuum flask which he used in conjunction with research into the liquefaction of gases

Carl von Linde

German scientist, engineer, and businessman who discovered a refrigeration cycle and invented the first industrial-scale air separation and gas liquefaction processes, which lead to the first reliable and efficient compressed-ammonia refrigerator in 1876