Chemistry Chemistry Practice Problems Solutions Library

Entropy Solutions Library

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260 solutions

Entropy

Q. What do we call the part of the universe that is not part of the system?

Solved • Jun 30, 2020

Entropy

Q. The ΔH°vap for pure water is 40.65 kJ/mol. Calculate the ΔS°vap for pure water.

Solved • Apr 30, 2020

Entropy

Q. For each of these processes, is the entropy change positiveor negative?i.) The melting of ice cubes at -5 Celsiusii.) The dissolving of sugar in ho...

Solved • Apr 30, 2020

Entropy

Q. In a chemical reaction two gases combine to form a solid. What do you expect the sign of ΔS to be?

Solved • Apr 30, 2020

Entropy

Q. Why does the entropy of a gas increase when it expands into a vacuum?

Solved • Apr 29, 2020

Entropy

Q. Predict how the entropy of the substance is affected in the following processes: a) Ar(l) → Ar(g)b) Cu(s, 300 K) → Cu(s, 800 K)c) H2O (g, 75 Torr, ...

Solved • Apr 28, 2020

Entropy

Q. Calculate the standard entropy change for the reaction2Mg(s) + O2(g) → 2MgO(s)using the data from the following table: Substance ?H?f (kJ/mol)?G?f ...

Solved • Apr 21, 2020

Entropy

Q. Calculate the standard entropy change for the following reaction at 25 °C.MgCl2(s)+H2O(l) → MgO(s)+2HCl(g).ΔS rxn = ?

Solved • Apr 15, 2020

Entropy

Q. Using the following data, Calculate ΔSfus and Δvap for HBr.Determine the entropy change when 4.80 mol of HBr (f) freezes at atmospheric pressure. 

Solved • Apr 13, 2020

Entropy

Q. Using the following data, Compound  Melting Point (C)  delta Hfus (kJ/mol)  Boiling Point (C)  delta H vap  HF -83.11 4.577 19.54 25.18 HCl -114.3 ...

Solved • Apr 9, 2020

Entropy

Q. Using the following data,Calculate ?Sfus and ?Svap for Cs.

Solved • Mar 25, 2020

Entropy

Q. Find delta S for the formation of 1 mole of PCl5 (g) for its elements

Solved • Mar 20, 2020

Entropy

Q. Using the following data,calculate ΔSfus and ΔSvap for Rb.

Solved • Mar 20, 2020

Entropy

Q. Using the following data,CompoundMelting Point (°C)   ?Hfus (kJ/mol) Boiling Point (°C)   ?Hvap (kJ/mol) HF -83.11 4.577 19.54 25.18 HCl -114.3 1.9...

Solved • Mar 18, 2020

Entropy

Q. Using the following data, Compound     Melting point (°C)     ΔHfus (kJ/mol)     Boiling point (°C)     ΔHvap (kJ/mol)HF                   -83.11  ...

Solved • Mar 17, 2020

Entropy

Q. Predict how the entropy of the substance is affected in the following processes: a) O2(g, 200 kPa, 300 K) → O2(g, 100 kPa, 300 K)b) I2(g, 1 bar, 12...

Solved • Mar 13, 2020

Entropy

Q. 1. Using the following data,Calculate ∆Sfus and ∆Svap for Na.ΔSfus = J•K-1•mol-1ΔSvap = J•K-1•mol-12. Using the following data,calculate the ΔSfus ...

Solved • Mar 13, 2020

Entropy

Q. Classify each process by its individual effect on the entropy of the universe, S. Drag the appropriate items to their respective bins.

Solved • Mar 12, 2020

Entropy

Q. For which of the following reactions is ∆S° > 0 at 25°C?A) 2H2(g) + O2(g) → 2H2O(g)B) 2ClBr(g) → Cl2(g) + Br2(g)C) I2(g) → I2(s)D) 2NO(g) + O2(g...

Solved • Feb 18, 2020

Entropy

Q. Calculate ∆S°for the reaction4Cr(s)      +      3O2(g)      →      2Cr2O3(s)Substance:                 Cr(s)              O2(g)               Cr2O3...

Solved • Feb 18, 2020

Entropy

Q. Which relationship or statement best describes ∆S° for the following reaction?2NH3(g) + 2ClF3(g) → 6HF(g) + N2(g) + Cl2(g)A) ∆S° ≈ 0B) ∆S° < 0C)...

Solved • Feb 18, 2020

Entropy

Q. Which relationship or statement best describes ∆S° for the following reaction?2 H2(g) + O2(g) → 2 H2O (l)A) ∆S° < 0B) ∆S° > 0C) ∆S° ≈ 0D) ∆S°...

Solved • Feb 18, 2020

Entropy

Q. Which of the following should have the greatest molar entropy, Sf, at 298 K?A) NH3(l)B) H2O(l)C) NaCl(s)D) N2O4(g)E) H2(g)

Solved • Feb 18, 2020

Entropy

Q. Which one of the following processes produces a decrease in the entropy of the system?A) boiling water to form steamB) melting ice to form waterC) ...

Solved • Jan 28, 2020

Entropy

Q. TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false.The entropy of a pure crystalline substance at 0 °C is zero.

Solved • Jan 28, 2020

Entropy

Q. Which of the following result(s) in a decrease in the entropy of the system? I. NH3(1 atm, 298 K) → NH3(3 atm, 298 K) II. Br2(g) → Br2(l) III. NaBr...

Solved • Dec 19, 2019

Entropy

Q. For each pair of substances, at the same temperature, choose the one with the higher entropy:I. (i) I2(l) (ii) I2(s)II. (i) PCl3(g) (ii) PCl5(g)III...

Solved • Dec 19, 2019

Entropy

Q. Which of the following result(s) in an increase in the entropy of the system?I. condensation of a gas to a liquidII. decreasing the volume of 1.0 m...

Solved • Dec 18, 2019

Entropy

Q. Which involves the greatest increase in entropy?a. H2O(l, 100°C) → H2O(s, 0°C)b. H2O(g, 100°C) → H2O(s, 0°C)c. H2O(g, 100°C) → H2O(l, 100°C)d. H2O(...

Solved • Dec 18, 2019

Entropy

Q. Which of the following reactions will have a negative value of ΔS?(i) Ba2+(aq) + SO42-(aq) → BaSO4(s)(ii) 2 Na(s) + 2 H2O(l) → 2 NaOH(aq) + H2(g)(i...

Solved • Dec 17, 2019

Entropy

Q. Which of the following reactions will have a negative value of ∆S?(i) Ba2+(aq) + SO42-(aq) → BaSO4(s)(ii) 2 Na(s) + 2H2O(l) → 2 NaOH(aq) + H2(g)(ii...

Solved • Dec 16, 2019

Entropy

Q. When does entropy increase and when does it decrease?

Solved • Aug 7, 2019

Entropy

Q. The element gallium (Ga) freezes at 29.8°C, and its molar enthalpy of fusion is ΔH fus = 5.59kJ/mol.1. When molten gallium solidifies to Ga(s) at i...

Solved • Jul 10, 2019

Entropy

Q. Predict which of the following compounds follow Trouton's rule:

Solved • Jul 9, 2019

Entropy

Q. For each of the following pairs, predict which substance possesses the larger entropy per mole.Compare 1 mol of O2(g)  at 300 oC, 0.01 atm and 1 mo...

Solved • Jan 3, 2019

Entropy

Q. In chemical kinetics, the entropy of activation is the entropy change for the process in which the reactants reach the activated complex.Predict ...

Solved • Jan 3, 2019

Entropy

Q. For each of the following pairs, predict which substance has the higher entropy per mole at a given temperature.He(l) or He(g).

Solved • Jan 3, 2019

Entropy

Q. For each of the following pairs, predict which substance has a higher entropy per mole at a given temperature.He(g) at 5 atm pressure or He(g) at 1...

Solved • Jan 3, 2019

Entropy

Q. If the normal boiling point of a liquid is 67 oC, and the standard molar entropy change for the boiling process is +100 J/K, estimate the standard ...

Solved • Jan 3, 2019

Entropy

Q. Indicate whether each statement is true or false.Unlike enthalpy, where we can only ever know changes in H, we can know absolute values of S.

Solved • Jan 3, 2019

Entropy

Q. If energy can flow in and out of the system to maintain a constant temperature during the process, what can you say about the entropy change of the...

Solved • Jan 3, 2019

Entropy

Q. Does the entropy of the system increase, decrease, or stay the same for each of the following conditions.

Solved • Jan 3, 2019

Entropy

Q. Entropy decreases when NO(g) is oxidized by O2(g) to NO2(g).What major factor leads to a decrease in entropy as the reaction shown takes place?

Solved • Jan 3, 2019

Entropy

Q. The diagram shows the variation in entropy with temperature for a substance that is a gas at the highest temperature shown.Why is the entropy chang...

Solved • Jan 3, 2019

Entropy

Q. How does the entropy of the system change when a solid melts, a gas liquefies, a solid sublimes?

Solved • Jan 3, 2019

Entropy

Q. Estimate whether the entropy of the system increases or decreases during each process.(a) photodissociation of O2 (g),(b) formation of ozone from o...

Solved • Jan 3, 2019

Entropy

Q. For which of the following processes does the entropy of the system increase?(a) the ripening of a banana,(b) dissolution of sugar in a cup of hot ...

Solved • Jan 3, 2019

Entropy

Q. Predict the sign of the entropy change of the system for each of the following reactions.(a) N2 (g) + 3H2 (g)  →  2NH3 (g)(b) CaCO3(s)  →  CaO(s) +...

Solved • Jan 3, 2019

Entropy

Q. Which process has the larger entropy change: melting ice or boiling water?

Solved • Jan 3, 2019

Entropy

Q. Calculate the change in entropy that occurs in the system when 30.5 g of acetone (C3H6O) vaporizes from a liquid to a gas at its normal boiling poi...

Solved • Jan 3, 2019

Entropy

Q. Calculate the change in entropy that occurs in the system when 45.0 g of acetone (C3H6O) freezes at its melting point (-94.8 ˚C). ΔHfus = 5.69 kJ/mol.

Solved • Jan 3, 2019

Entropy

Q. Calculate ΔS˚rxn for the balanced chemical equation2 H2S(g) + 3 O2(g)  →  2 H2O(g) + 2 SO2(g)Standard enthalpies for selected substances at 25oC Su...

Solved • Jan 3, 2019

Entropy

Q. Without doing any calculations, determine the sign of ΔSsys for each of the following chemical reactions.a. Mg(s) + Cl2(g) → MgCl2(s)b. 2 H2S(g) + ...

Solved • Jan 3, 2019

Entropy

Q. Rank the following substances in order of decreasing standard molar entropy (S˚).a. I2(g); F2(g); Br2(g); Cl2(g)b. H2O(g); H2O2(g); H2S(g)c. C(s, g...

Solved • Jan 3, 2019

Entropy

Q. Without doing any calculations, determine the sign of ΔSsys and ΔSsurr for each of the chemical reactions below.2 CO(g) + O2(g) ⇌ 2 CO2(g), ΔH˚rxn ...

Solved • Jan 3, 2019

Entropy

Q. Without doing any calculations, determine the sign of ΔSsys and ΔSsurr for each of the chemical reactions below.2 NO2(g) → 2 NO(g) + O2(g), ΔH˚rxn ...

Solved • Jan 3, 2019

Entropy

Q. Which reaction is most likely to have a positive ΔSsys?a) SiO2(s) + 3 C(s) → SiC(s) + 2 CO(g)b) 6 CO2(g) + 6 H2O(g) → C6H12O6(s) + 6 O2(g)c) CO(g) ...

Solved • Jan 3, 2019

Entropy

Q. Arrange the gases – F2, Ar, and CH3F – in order of increasing standard entropy (S˚) at 298 K.

Solved • Jan 3, 2019

Entropy

Q. Use standard entropies to calculate ΔS˚rxn for the balanced chemical equation: 2 PCl3(l) + O2(g) →  2 POCl3(l)SubstanceΔS˚ (J/mol•K)POCl3(l)222.5PO...

Solved • Jan 3, 2019

Entropy

Q. Given the data, calculate ΔSvap for each liquids. (ΔSvap = ΔHvap/T, where T is in K)CompoundNameBP (oC)ΔHvap (kJ/mol) at BPC4H10ODiethyl ether34.62...

Solved • Jan 3, 2019

Entropy

Q. Determine the sign of ΔSsys in each of the following processes: dry ice subliming

Solved • Jan 3, 2019

Entropy

Q. Calculate ΔS˚rxn for each of the reactions given below.3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

Solved • Jan 3, 2019

Entropy

Q. Find ΔS˚ for the formation of CH3Cl(g) { m CH}_3{ m Cl}(g) from its elements in their standard states.

Solved • Jan 3, 2019

Entropy

Q. Calculate ΔSsurr at the indicated temperature for a reaction.ΔH˚rxn = –279 kJ; 298 K

Solved • Jan 3, 2019

Entropy

Q. Calculate ΔSsurr at the indicated temperature for a reaction.ΔH˚rxn = 128 kJ; 73 K

Solved • Jan 3, 2019

Entropy

Q. Use data from Appendix IIB in the textbook to calculate ΔS˚rxn for each of the following reactions.C2H4(g) + H2(g) → C2H6(g)

Solved • Jan 3, 2019

Entropy

Q. Without doing any calculations, determine the sign of ΔSsys for each of the following chemical reactions.a. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)...

Solved • Jan 3, 2019

Entropy

Q. Consider these three changes in the possible distributions of six gaseous particles within three interconnected boxes. Which change has a positive ΔS?

Solved • Jan 3, 2019

Entropy

Q. Given the thermodynamic data below, calculate ΔS and ΔS surr for the following reaction at 25°C and 1 atm:                       XeF  6(g) →XeF4(s)...

Solved • Dec 3, 2018

Entropy

Q. For rubidium ΔH°vap = 69.0 kJ/mol at 686°C, its boiling point. Calculate ΔS°, and q for the vaporization of 1.00 mole of rubidium at 686°C and 1.00...

Solved • Dec 3, 2018

Entropy

Q. Rank the contents of the following containers in order of decreasing entropy.

Solved • Dec 3, 2018

Entropy

Q. Predict the sign of ΔS° and then calculate ΔS° for each of the following reactions.b. 2SO3 (g) → 2SO2 (g) + O2 (g)

Solved • Nov 30, 2018

Entropy

Q. For each of the following pairs, which substance has the greater value of S?b. N2O(g) (at 1 atm, 25°C) or He(g) (at 1 atm, 25°C)

Solved • Nov 30, 2018

Entropy

Q. The enthalpy of vaporization of ethanol is 38.7 kJ/mol at its boiling point (78°C). Determine ΔSsys, ΔSsurr, and ΔSuniv when 1.00 mole of ethanol i...

Solved • Nov 30, 2018

Entropy

Q. Ethanethiol (C2H5SH; also called ethyl mercaptan) is commonly added to natural gas to provide the “rotten egg” smell of a gas leak. The boiling poi...

Solved • Nov 30, 2018

Entropy

Q. Calculate ΔSsurr for the following reactions at 25°C and 1 atm.a. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)     ΔH° = -2221 kJ

Solved • Nov 30, 2018

Entropy

Q. Use the standard entropy data in Appendix G to determine the change in entropy for each of the reactions listed below. All the processes occur at t...

Solved • Nov 29, 2018

Entropy

Q. By calculating ΔSuniv at each temperature, determine if the melting of 1 mole of NaCl(s) is spontaneous at 500 °C and at 700 °C.What assumptions ar...

Solved • Nov 29, 2018

Entropy

Q. Using the relevant S°298 values listed in Appendix G, calculate ΔS°298 for the following change:(a) N2(g) + 3H2(g) ⟶ 2NH3(g)

Solved • Nov 29, 2018

Entropy

Q. Determine the entropy change for the combustion of gaseous propane, C 3H8, under the standard conditions to give gaseous carbon dioxide and water.

Solved • Nov 29, 2018

Entropy

Q. Calculate ΔS°298 for the following change.(a) SnCl4(l) ⟶ SnCl4(g)

Solved • Nov 29, 2018

Entropy

Q. The boiling point of chloroform, CHCl 3, is 61.2°C. Use Trouton’s rule to estimate the enthalpy of vaporization of chloroform.

Solved • Nov 28, 2018

Entropy

Q. Iron melts at 1535°C and its enthalpy of fusion is 13.8 kJ/mol. Calculate the entropy of fusion per mole of iron.

Solved • Nov 28, 2018

Entropy

Q. When heated, the DNA double helix separates into two random coil single strands. When cooled, the random coils reform the double helix: double heli...

Solved • Nov 28, 2018

Entropy

Q. Consider the following reaction:   2NOBr(g) ⥫⥬ 2NO(g) + Br 2(g)      K = 0.42 at 373 KGiven that S° of NOBr(g) = 272.6 J/mol·K and that ΔS°rxn and ...

Solved • Nov 28, 2018

Entropy

Q. Write the balanced chemical equation for the combustion of methane, CH4(g), to give carbon dioxide and water vapor. Explain why it is difficult to ...

Solved • Nov 26, 2018

Entropy

Q. Consider two processes: sublimation of I2 (s) and melting of I2 (s) (Note: the latter process can occur at the same temperature but somewhat higher...

Solved • Nov 26, 2018

Entropy

Q. At room temperature, the entropy of the halogens increases from I2 to Br2 to Cl2. Explain.

Solved • Nov 26, 2018

Entropy

Q. Arrange the following set of systems in order of increasing entropy. Assume one mole of each substance and the same temperature for each member of ...

Solved • Nov 26, 2018

Entropy

Q. Calculate ΔSuniv for the formation of CH3OH(l) from its elements, and state whether the reaction is spontaneous at 298 K.

Solved • Nov 21, 2018

Entropy

Q. Find ΔS°rxn for the formation of CH3OH(l) from its elements.

Solved • Nov 21, 2018

Entropy

Q. Find ΔS°rxn for the formation of HI(g) from its elements.

Solved • Nov 21, 2018

Entropy

Q. Calculate ΔSuniv for the formation of Cu2O(s) from its elements, and state whether the reaction is spontaneous at 298 K.

Solved • Nov 21, 2018

Entropy

Q. Find ΔS°rxn for the formation of Cu2O(s) from its elements.

Solved • Nov 21, 2018

Entropy

Q. Find ΔS°rxn for the combustion of ammonia to nitrogen dioxide and water vapor. Is the sign of ΔS°rxn as expected?

Solved • Nov 21, 2018

Entropy

Q. Find ΔS°rxn for the combustion of ethane (C2H6) to carbon dioxide and gaseous water. Is the sign of ΔS°rxn as expected?

Solved • Nov 21, 2018

Entropy

Q. For the following reaction, predict the sign and find the value of ΔS°rxn:(a) 3NO2(g) + H2O(l) ⟶ 2HNO3(l) + NO(g)

Solved • Nov 21, 2018

Entropy

Q. Without consulting Appendix B, arrange the group in order of increasing standard molar entropy (S°). Explain.(c) SF6(g), SF4(g), S2F10(g)

Solved • Nov 21, 2018

Entropy

Q. Predict which substance has greater molar entropy. Explain.(a) P4(g) or P2(g)(b) HNO3(aq) or HNO3(l)(c) CuSO4(s) or CuSO4·5H2O(s)

Solved • Nov 21, 2018

Entropy

Q. Predict which substance has greater molar entropy. Explain.(a) CH3OH(l) or C2H5OH(l)(b) KClO3(s) or KClO3(aq)(c) Na(s) or K(s)

Solved • Nov 21, 2018