Accounting
Anthropology
Archaeology
Art History
Banking
Biology & Life Science
Business
Business Communication
Business Development
Business Ethics
Business Law
Chemistry
Communication
Computer Science
Counseling
Criminal Law
Curriculum & Instruction
Design
Earth Science
Economic
Education
Engineering
Finance
History & Theory
Humanities
Human Resource
International Business
Investments & Securities
Journalism
Law
Management
Marketing
Medicine
Medicine & Health Science
Nursing
Philosophy
Physic
Psychology
Real Estate
Science
Social Science
Sociology
Special Education
Speech
Visual Arts
Science
Q:
The standard molar entropy for Br2(g) is 245.46 J/(mol K) at 25C. Given that S = 104.58 J/K for the dissociation of one mole of Br2(g) into Br(g) at 25C, find the standard molar entropy for Br(g) at 25C.A) 70.44 J/(mol K)B) 140.08 J/(mol K)C) 175.02 J/(mol K)D) 350.04 J/(mol K)
Q:
Calculate S for the formation of one mole of solid sodium bromide from the elements at 25C.A) -116.7 J/KB) -81.2 J/KC) -40.5 J/KD) 86.8 J/K
Q:
S = -198.7 J/K for the reaction shown below. Calculate S for NH3(g).N2(g) + 3 H2(g) -> 2 NH3(g)A) 61.7 J/K molB) 123.4 J/K molC) 192.3 J/K molD) 384.6 J/K mol
Q:
Calculate S for the following reaction.N2(g) + 2 O2(g) -> 2 NO2(g)A) -156.5 J/KB) -121.5 J/KC) 15.5 J/KD) 636.5 J/K
Q:
Which one of the following has the lowest standard molar entropy, S, at 25C?
A) C8H18(s)
B) C8H18(l)
C) C12H26(s)
D) C12H26(l)
Q:
Which substance has the highest standard molar entropy at 25C?
A) C(graphite)
B) C2H4(g)
C) CH3OH(l)
D) MgCO3(s)
Q:
Which of the following gas molecules has the greatest standard molar entropy at 25C?
A) C2H2
B) CH2CH2
C) CH3CH3
D) All have the same entropy.
Q:
Which has the highest standard molar entropy at 25C?
A) F2(g)
B) Cl2(g)
C) Br2(g)
D) I2(g)
Q:
Which has the highest standard molar entropy at 25C?
A) Al(s)
B) Al(l)
C) Al(g)
D) All three should have a standard molar entropy of zero.
Q:
Under which of the following conditions would one mole of Ne have the highest entropy, S?
A) 27C and 25 L
B) 137C and 25 L
C) 27C and 35 L
D) 137C and 35 L
Q:
Which of the following statements must be true for the entropy of a pure solid to be zero?
I. The temperature must be 0 K.
II. The solid must be crystalline, not amorphous.
III. The solid must be perfectly ordered.
IV. The solid must be an element.
A) I
B) I and II
C) I, II, and III
D) I, II, III, and IV
Q:
According to the third law of thermodynamics,
A) energy is conserved in any transformation of matter.
B) the entropy increases for any spontaneous process.
C) the entropy of a perfectly ordered, crystalline substance is zero at 0 Kelvin.
D) the entropy of the universe increases for any spontaneous process.
Q:
Which provides the greatest increase in entropy?A) H2O (s, 0C) -> H2O (l, 0C)B) H2O (l, 0C) -> H2O (l, 25C)C) H2O (g, 0.1C) -> H2O (s, 0.1C)D) H2O (l, 100C) -> H2O (g, 100C)
Q:
Which has the highest entropy in each set?
I. H2O(s), H2O(l), H2O(g) at 0.1C, 4.58 atm
II. H2O(l) at 0C, H2O(l) at 25C, H2O(l) at 100C (all at 1.0 atm pressure)
A) H2O(l) in set I and H2O(l) at 0C in set II
B) H2O(s) in set I and H2O(l) at 100C in set II
C) H2O(g) in set I and H2O(l) at 0C in set II
D) H2O(g) in set I and H2O(l) at 100C in set II
Q:
Which has the lowest entropy?A) CH3OH(s, -25C)B) CH3OH(s, -15C)C) CH3OH(l, 15C)D) CH3OH(l, 25C)
Q:
What is the sign of S for each of the following processes?I. The separation of gaseous molecules of UF6, into 238UF6 and 235UF6 atconstant temperature and pressure.II. The dissolving of I2(s) in CCl4(l).A) S is negative for I and negative for II.B) S is negative for I and positive for II.C) S is positive for I and negative for II.D) S is positive for I and positive for II.
Q:
The Boltzmann formula is S = k ln W. A perfect crystal has a molar entropy of 0 at absolute zero because
A) W = 0.
B) W = 1.
C) W = NA.
D) k = 1.
Q:
Assume a heteronuclear diatomic molecule, AB, forms a one-dimensional crystal by lining up along the x-axis. Also assume that each molecule can only have one of six possible orientations, corresponding to atom A facing in either the positive or negative direction along the x-, y-, or z-axis. If the molecules are arranged randomly in the six directions, the molar entropy at absolute zero should be
A) R ln 6.
B) R ln 66.
C) R ln 6!
D) 0.
Q:
Predict the sign of S for each of the following processes, which occur at constant temperature.I. The volume of 2.0 moles of O2(g) increases from 44 L to 52 L.II. The pressure of 2.0 moles of O2(g) increases from 1.0 atm to 1.2 atm.A) I: S= negative; II: S= negativeB) I: S= negative; II: S= positiveC) I: S= positive; II: S= negativeD) I: S= positive; II: S= positive
Q:
What is the entropy change associated with the expansion of one mole of an ideal gas from an initial volume of V to a final volume of V of 2.50V at constant temperature?A) S = 2.50 R ln (Vf/Vi)B) S = -2.50 R ln (Vf/Vi)C) S = R ln 2.50D) S = -R ln 2.50
Q:
The entropy change associated with the expansion of one mole of an ideal gas from an initial volume ofVi to a final volume of Vf at constant temperature is given by the equation, S = R ln (Vf/Vi). What is the entropy change associated with the expansion of three moles of an ideal gas from an initial volume of Vi to a final volume of Vf at constant temperature?A) S = R ln (Vf/Vi)B) S = 3 mol R ln (Vf/Vi)C) S = R ln (Vf 23/Vi)D) S = R ln (Vf 3!/Vi)
Q:
What is k in Boltzmann's formula, S = k ln W?
A) the degeneracy of the state
B) the equilibrium constant for the process
C) the universal gas constant divided by Avogadro's number
D) the universal gas constant times Avogadro's number
Q:
An electron in an oxygen p orbital on which of the following would have the highest entropy?A) CH3CH2OHB) CH3CH2O-C) CH3CO2OHD) CH3CO2-
Q:
Which electron on an atom of copper would have the highest value of W in the Boltzmann formula?
A) 3s
B) 3d
C) 4s
D) 4p
Q:
What is the entropy of 105 molecules in 1010 boxes?
A) 1.59 10-21
B) 3.45 10-20
C) 1.38 10-17
D) 3.18 10-17
Q:
What is W in Boltzmann's formula, S = k ln W?
A) a fraction indicating the probability of obtaining a result
B) a random number
C) the number of ways of obtaining the state
D) the work times Avogadro's number
Q:
The brown color associated with photochemical smog is due to NO2(g), which is involved in an equilibrium with N2O4(g) in the atmosphere.2 NO2(g) N2O4(g)Predict the signs of the enthalpy and entropy change for the forward reaction.A) The enthalpy change is negative and the entropy change is negative.B) The enthalpy change is negative and the entropy change is positive.C) The enthalpy change is positive and the entropy change is negative.D) The enthalpy change is positive and the entropy change is positive.
Q:
Sodium reacts violently with water according to the equation:2 Na(s) + 2 H2O(l) -> 2 NaOH(aq) + H2(g)The resulting solution has a higher temperature than the water prior to the addition of sodium. What are the signs of H and S for this reaction?A) H is negative and S is negative.B) H is negative and S is positive.C) H is positive and S is negative.D) H is positive and S is positive.
Q:
Without doing any calculations, determine whether the standard entropy change, S is positive or negative for each of the following reactions.reaction 1: S(s, rhombic) + O2(g) -> SO2(g)reaction 2: 2 SO2(g)+ O2(g) ->2 SO3(g)A) S is positive for both reactions.B) S is positive for reaction 1 but negative for reaction 2.C) S is positive for reaction 2 but negative for reaction 1.D) S is positive for both reactions.
Q:
Without doing any calculations, determine whether the standard entropy change, S is positive or negative for each of the following reactions.reaction 1: C(graphite) + O2(g) -> CO2(g)reaction 2: 2 CO(g) + O2(g) -> 2 CO2(g)A) S is positive for both reactions.B) S is positive for reaction 1 but negative for reaction 2.C) S is positive for reaction 2 but negative for reaction 1.D) S is negative for both reactions.
Q:
Predict the sign of S of the system for both of the following.I. 2 C(graphite) + O2(g) -> 2 CO(g)II. C4H10(g) -> C4H10(l)A) S should be negative for I and negative for II.B) S should be negative for I and positive for II.C) S should be positive for I and negative for II.D) S should be positive for I and positive for II.
Q:
For which process is the sign of S negative in the system?A) 2 H2(g) + O2(g) -> 2 H2O(g)B) 2 H2O(l) + 2 K(s) -> 2 K+(aq) +2 OH-(aq) + H2(g)C) H2O(s) -> H2O(g)D) H2O(l) -> H2O(g)
Q:
For which of the following will the entropy of the system increase?
A) condensation of steam
B) reaction of magnesium with oxygen to form magnesium oxide
C) reaction of nitrogen and hydrogen to form ammonia
D) sublimation of dry ice
Q:
Entropy is a measure of
A) free energy.
B) the heat of a reaction.
C) molecular randomness.
D) the rate of a reaction.
Q:
Which of the following processes is spontaneous?
A) a mixture of two gases separating into pure compounds
B) reaction of sodium with oxygen
C) precipitation of solute from a saturated solution
D) water flowing uphill
Q:
Which of the following processes are spontaneous?
I. dissolving more solute in an unsaturated solution
II. dissolving more solute in a saturated solution
III. dissolving more solute in a supersaturated solution
A) none of these
B) I
C) I and II
D) I, II, and III
Q:
The reaction A(g) -> B(g) is spontaneous under standard conditions. Which of the following statements must be true?I. The reaction B(g) -> A(g) is nonspontaneous under standard conditions.II. A(g) will be completely converted to B(g) if sufficient time is allowed.III. A(g) will be completely converted to B(g) rapidly.A) none of theseB) IC) I and IID) I, II, and III
Q:
Classify each of the following processes as spontaneous or nonspontaneous.I. H2O(l) -> H2O(g) T = 25C, vessel open to atmosphere with 50% relative humidityII. H2O(s) -> H2O(l) T = 25C, P = 1 atmA) I and II are both spontaneous.B) I is spontaneous and II is nonspontaneous.C) I is nonspontaneous and II is spontaneous.D) I and II are both nonspontaneous.
Q:
The chemical system shown below is at equilibrium. Which change in conditions will not result in a spontaneous forward reaction?N2(g) + 3 H2(g) 2 NH3(g) Kp = 4 105A) adding a catalystB) adding more H2C) adding more N2D) reducing the volume
Q:
Which forward reaction is a nonspontaneous process?A) the expansion of a gas into a vacuumB) N2(g) + 3 H2(g) 2 NH3(g) if PH2 = PN2 = 1 atm, PNH3 = 0, and Kp = 4 105C) 2 NH3(g) N2(g) + 3 H2(g) if PNH3 = 1 atm,PH2 = PN2 = 0, andKp = 2 10-6D) None of these
Q:
Which of the following statements is not true?
A) The reverse of a spontaneous reaction is always nonspontaneous.
B) A spontaneous process always moves toward equilibrium.
C) A nonspontaneous process cannot be caused to occur.
D) A highly spontaneous process need not occur rapidly.
Q:
For the vaporization of solid rhombic sulfur, S(s, rhombic) S(g), G = 236.7 kJ/mol. At 25 C the vapor pressure of rhombic sulfur is ________ atm.
Q:
The reaction 2 H2O(g) + CO2(g) -> CH4(g) + 2 CO2(g) is nonspontaneous at 25C. The addition of a catalyst will ________ (decrease, increase, not change) the rate of reaction and ________ (decrease, increase, not change) the spontaneity of the reaction.
Q:
The reaction 2 H2(g) + O2(g) -> 2 H2O(g) is spontaneous at 25C. The addition of a catalyst will ________ (decrease, increase, not change) the rate of reaction and ________ (decrease, increase, not change) the spontaneity of the reaction.
Q:
For the reaction N2(g) + 2 O2(g) -> 2 NO2(g), G = 102.6 kJ. At 25C the equilibrium constant Kp = ________.
Q:
The standard free energy for a reaction is G = -33.0 kJ. At 25C the equilibrium constant for this reaction, Kp = ________.
Q:
Standard free energies of formation, G, in kJ/mol, are given below each reactant and product in the reaction shown below. The standard free energy of reaction, G, for this reaction is ________ kJ.CH4(g) + 2 O2(g) -> CO2(g) + 2 H2O(l)-50.8 0 -394.4 -237.2
Q:
Acetylene, C2H2, has a standard enthalpy of formation, H = 226.7 kJ/mol, and a standard entropy change for its formation from its elements, S = 58.8 J/K mol. The standard free energy of formation of acetylene is ________ kJ/mol.
Q:
For the reaction N2(g) + 2 O2(g) -> 2 NO2(g), H = 66.4 kJ/mol and S = -121.5 J/K. Is there a temperature at which the spontaneity of this reaction be changed, either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so, estimate the temperature.
Q:
For the reaction N2(g) + O2(g) -> 2NO(g), H = 180.4 kJ/mol and S = 24.9 J/K. Is there a temperature at which the spontaneity of this reaction be changed, either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so, estimate the temperature.
Q:
A reaction has G = + 21.5 kJ/mol, H = + 25.0 kJ/mol, and S= +15.0 J/mol K can become spontaneous at a temperature of ________ K.
Q:
A reaction for which H = + 98.8 kJ and S = + 141.5 J/K is ________ (spontaneous or nonspontaneous) at low temperatures and ________ (spontaneous or nonspontaneous) at high temperatures.
Q:
For the reaction N2(g) +2 O2(g) -> 2 NO2(g), H = 66.4 kJ/mol and S = -121.5 J/K. Stotal for this reaction is ________ J/K, and the reaction is ________ (spontaneous, nonspontaneous) at 25C.
Q:
For the reaction N2(g) +O2(g) -> 2 NO(g), H = 180.4 kJ/mol and S = 24.9 J/K. Stotal for this reaction is ________ J/K, and the reaction is ________ (spontaneous, nonspontaneous) at 25C
Q:
The most common white pigment until the 1880s was lead white, sometimes called basic lead carbonate: (PbCO3)2Pb(OH)2. Paintings containing lead white turned black in the presence of moist H2S from natural sources and polluted air due to the formation of PbS. The PbCO3 portion of this reaction is shown below.PbCO3(s) + H2S(aq) -> PbS(s) + H2CO3(aq)If H = -60.9 kJ/mol and S = 26.6 J/K, what are Ssurr and Stotal for this reaction at 25C??
Q:
The most commonly used white pigment is titanium white, which is titanium(IV) oxide, TiO2. Titanium white can be formed from TiCl4 as shown in the reaction below.TiCl4(l) + 2 H2O(l) -> TiO2(s) + 4 HCl(g)If H = 61.9 kJ/mol and S = 405.4 J/K, what are Ssurr and Stotal for this reaction at 25C?
Q:
Standard molar entropies, S, in J/Kmol, are given below each reactant and product in the reaction shown below. The standard entropy of reaction, S, for this reaction is ________ J/K.2 SO2(g)+ O2(g) -> 2 SO3(g)248.1 205.0 256.6
Q:
Standard molar entropies, S, in J/Kmol, are given below each reactant and product in the reaction shown below. The standard entropy of reaction, S, for this reaction is ________ J/K.S(s, rhombic) + O2(g) -> SO2(g)31.8 205.0 248.1
Q:
Standard molar entropies, S, in J/K mol, are given below each reactant and product in the reaction shown below. The standard entropy of reaction, S, for this reaction is ________ J/K.CH4(g) + 2 O2(g) -> CO2(g) + 2 H2O(l)186.2 205.0 213.6 69.9
Q:
The entropy of water at 25 is ________ than the entropy of water at 35C.
Q:
The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid H2X+) are Ka1 = 4.6 10-3 and Ka2 = 2.0 10-10. What is the pH of 50.00 mL of a 0.100 M solution of alanine after 100.00 mL of 0.100 M NaOH has been added?
A) 9.70
B) 10.69
C) 11.11
D) 12.70
Q:
The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid, H2X+) are Ka1 = 4.6 10-3 and Ka2 = 2.0 10-10. What is the pH of 50.00 mL of a 0.050 M solution of alanine after 37.50 mL of 0.100 M NaOH has been added?
A) 4.85
B) 6.02
C) 7.39
D) 9.70
Q:
The dissociation equilibrium constants for the protonated form of alanine (a diprotic amino acid, H2X+) are Ka1 = 4.6 10-3 and Ka2 = 2.0 10-10. What is the pH of 50.00 mL of a 0.0500 M solution of alanine after 25.00 mL of 0.100 M NaOH has been added?
A) 2.34
B) 4.85
C) 5.59
D) 6.72
Q:
Oxalic acid, H2C2O4 has acid dissociation constants Ka1 = 5.9 10-2 and Ka2 = 6.4 10-5.What is the pH after 20.00 mL of 0.0500 M NaOH is added to 5.00 mL of 0.2000 M H2C2O4?A) 1.23B) 2.10C) 2.80D) 4.19
Q:
Sulfurous acid, H2SO3 has acid dissociation constants Ka1 = 1.5 10-2 and Ka2 = 6.3 10-8. What is the pH after 10.00 mL of 0.1000 M NaOH is added to 10.00 mL of 0.1000 M H2SO3?A) 1.82B) 3.60C) 4.25D) 7.20
Q:
What is the pH of the resulting solution if 25 mL of 0.432 M methylamine, CH3NH2, is added to
15 mL of 0.234 M HCl? Assume that the volumes of the solutions are additive. Ka = 2.70 10-11 for CH3NH3+.
A) 3.11
B) 3.74
C) 10.26
D) 10.89
Q:
The equivalence point pH of the titration of four weak bases is given. Which is the strongest base?
A) 4.21
B) 5.67
C) 6.33
D) 7.58
Q:
Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 28.30 mL of 0.500 M HCl to reach the equivalence point?
A) 0.208 M
B) 0.353 M
C) 0.708 M
D) 1.21 M
Q:
Which of the following titrations result in an acidic solution at the equivalence point?
A) CH3COOH titrated with NaOH
B) KF titrated with KOH
C) HCl titrated with NaOH
D) C5H5N titrated with HCl
Q:
What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 40.00 mL of
0.10 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 10-5 for CH3CO2H.
A) 8.26
B) 9.26
C) 11.13
D) 12.15
Q:
What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 30.00 mL of
0.10 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 10-5 for CH3CO2H.
A) 5.28
B) 7.00
C) 8.72
D) 10.02
Q:
What is the pH of the resulting solution if 30.00 mL of 0.10 M acetic acid is added to 10.00 mL of 0.10 M NaOH? Assume that the volumes of the solutions are additive. Ka = 1.8 10-5 for CH3CO2H.
A) 9.56
B) 8.95
C) 5.05
D) 4.44
Q:
The equivalence point pH of the titration of four weak acids is given. Which is the strongest acid?
A) 7.24
B) 7.86
C) 8.12
D) 8.43
Q:
What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous formic acid requires 29.80 mL of 0.0567 M NaOH? Ka = 1.8 10-4 for formic acid.
A) 2.46
B) 5.88
C) 8.12
D) 11.54
Q:
What is the pH at the equivalence point of a weak acid-strong base titration?
A) pH < 7
B) pH = 7
C) pH > 7
D) pH = 14.00
Q:
Which of the following titrations result in a basic solution at the equivalence point?
A) HI titrated with NaCH3CO2
B) HOCl titrated with NaOH
C) HBr titrated with KOH
D) Pb(NO3)2 titrated with NaI
Q:
What is the pH of a solution made by mixing 30.00 mL of 0.10 M HCl with 40.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive.
A) 0.85
B) 1.85
C) 12.15
D) 13.15
Q:
What volume of 5.00 10-3 M HNO3 is needed to titrate 100.00 mL of 5.00 10-3 M Ca(OH)2 to the equivalence point?A) 12.5 mLB) 50.0 mLC) 100. mLD) 200. mL
Q:
At what pH is the amino acid glycine with a Ka of 2.51 10-10 sixty-six (66%) percent dissociated?
A) 9.60
B) 9.89
C) 10.10
D) 10.60
Q:
What is the percent dissociation of ascorbic acid if the solution has a pH = 5.50 and a pKa = 4.10?
A) 96%
B) 10%
C) 5%
D) 1%