Short Quizzes
2013 Fall
August 29
1. Write the 1st Law in Equation form.
Ans: DU = q - w
2. Circle the variables that are path functions T, P, q, w, U V.
Ans: q, wAugust 30
1. Write the definitions of Cp and Cv.
Ans: Cp = (dq/dt)p, Cv =(dq/dT)v
2. What does reversible mean?
Ans: A process from state A to state B is said to have been conducted reversibly if it could be returned to state A leaving no more than a vanishingly small change in the surroundings.Sept 4
How much work is required to isothermally compress an ideal gas at 300K and 1 atm to 10 atm?
Ans: dw = PdV = nRT dV/V; w = nRTln(V2/V1) but V2/V1 = P1/P2; w = 1 mole*8.31 J/(mol*K)*300Kln(1/10)Sept 5
Three moles of ideal monatomic gas at 300 K are adiabatically compressed to one tenth their original volume. What is the final temperature?
Ans: T2/T1 = (V1/V2)^(R/cv) = (V1/0.1V1)^(R/1.5R) =10^0.667; T2 = 300 K * 10^0.667; Note: independent of moles.Sept 6
How much work is required to adiabatically compress an ideal monatomic gas at 1 atm and 300 K to 1000 K?
Ans: DU = 0 - w, w = -ncvDT = -n(1.5R)(1000-300)K; per mole w = -1050K*R; R= 8.31 J/(mol*K)Sept 9
A Carnot Cycle composed of __________________
Ans: two reversible adiabaticsintersecting two isothermalsSept 11
What is the mathematical definition of efficiency for a Carnot heat engine?
Ans: e = w/qH = 1 + qL/qH = 1 - TL/THSept 12
How much work would it take to pump 1000 BTUs of heat into a sink at 300 K from a sink at 290 K? Assume a frictionless, no-mechaical-loss heat pump.
Ans: |qL|/|qH| = TL/TH, |qL| = 1000 BTU * 290/300, so w = 1000*10/300 (conservation of energy: qL ) or 100/3 BTUSept 13
What is the definiton of the thermodynamic temperature scale?
Ans: TL/TH = |qL|/|qH|Sept 16
What three ways to make a Carnot Cycle irreversible?
Ans:
1) Make the high temperature sink hotter than the gas along the high temperature path: TsH > TgH
2) Make the low temperature sink colder than the gas along the low temperature path: TsL < TgL
3) recover less than max work during th eisothermal gas expansion path: wA < wMaxSept 18
What is the 3rd Law of Thermodynamics?
Ans: The entropy for a pure crystalline material at absolute zero is zero.Sept 23
Write the Boltzman Equation for S. Describe each term.
Ans: S = klnW where k is Boltzman's Constant (r/Avogadro's NUmber) and W is th enumber of configurations.Sept 25
Show how to calculate DS for the mixing of 8 moles of argon with 2 moles of neon?
Ans: DS = - R[0.8ln(0.8) + 0.2ln(0.2)]10 gmoles R= 8.3144 J/(K*gmole)Sept 26
From what mathmatical properties are the following determined?
a) Other Thermo Relations Ans: The total differential
b) Maxwell Relations Ans: Thequality of exactnessSept 30
1) Write the a) so-called "Other Thermodynamic Relations and b) The Maxwell Realtion that derives from dU = TdS - PdV
2) What is the criteria of equilibrium at a) dT = dV =0 and b) dT = dV= 0
Ans: 1a ) T = (dU/dS)v and -P = (dU/dV)s; 1b) (dT/dV)s = - dP/dS)v; 2a) dA<= -dw' (or 0 if only PdV work); dG <= -dw' (or 0 if only PdV work)Oct 2
Write the Gibb's-Helmhotz Equation.
Oct 3
State the defination of the heat of formation.Oct 9
What are the 3 kinds of heat (enthalpy)?
Oct 10
What is the defination of chemical potential?
Oct 16
Print out any table from thermo-calc.
Oct 16
Write the Clausius and Clausius-Clapeyron Equations.
Oct 17
Print out any table from thermo-calc.
Oct 18
Draw a calculation schematic to find rhw AFT for combustion of C with O2 preheated to 800.
Oct 21
How does one find a (T, P) point of equilibrium if ΔG°>0 for all T's but ΔV <0?
Oct 23
Label the location of the s, l, g phases.
Oct 24
Write the Big Six Equations.
Oct 25
What is the Keq for the reaction
ZnO(s) + C(s) = CO(g) + Zn (l)
Oct 31
Attendeance for 10/31: name test.
Nov 3
What are the units for a) fugacity b) Keq?
Nov 4
Plot the fugacity coefficient result from integrating (z-1)/Pr dPr on the class handout of f'/p versus Pr.
Nov 6