Thermodynamic Quantities for Selected Substances at 298.15 K (25 °C) Substance AH°f (kJ/mol) AG°f (kJ/mol) S(K-mol) Calcum Ca (s) CaCl2 (s) 41.4 -795.8 -748.1 104.6 Caz* (aq) 226.7 209.2 200.8 Chlorine Cl2 (8) 222.96 Cl- (aq) -167.2 -131.2 56.5 Oxygen 02 (8) 205.0 H20 (1) -285.83 -237.13 69.91 Phosphorus P2 (g) PC13 (g) POC13 (g) 144.3 103.7 218.1 -288.1 -269.6 311.7 -542.2 -502.5 325 Sulfur 31.88 S (s, rhombic) -269.9 -300.4 248.5 90 3(g) -395.2 -370.4 256.2 The value of A G° at 25 °C for the decomposition of phosphorous trichloride into its constituent elements as shown. 2PCI3(g) --> P2(g) + 3CI2(g) is kJ/mol. A. -539.2 B. +539.2 C. -642.9 D. +642.9 O E. -373.3

Thermodynamic Quantities for Selected Substances at 298.15 K (25 °C) Substance AH°f (kJ/mol) AG°f (kJ/mol) S(K-mol) Calcum Ca (s) CaCl2 (s) 41.4 -795.8 -748.1 104.6 Caz* (aq) 226.7 209.2 200.8 Chlorine Cl2 (8) 222.96 Cl- (aq) -167.2 -131.2 56.5 Oxygen 02 (8) 205.0 H20 (1) -285.83 -237.13 69.91 Phosphorus P2 (g) PC13 (g) POC13 (g) 144.3 103.7 218.1 -288.1 -269.6 311.7 -542.2 -502.5 325 Sulfur 31.88 S (s, rhombic) -269.9 -300.4 248.5 90 3(g) -395.2 -370.4 256.2 The value of A G° at 25 °C for the decomposition of phosphorous trichloride into its constituent elements as shown. 2PCI3(g) --> P2(g) + 3CI2(g) is kJ/mol. A. -539.2 B. +539.2 C. -642.9 D. +642.9 O E. -373.3

Chemistry for Engineering Students

4th Edition

ISBN:9781337398909

Author:Lawrence S. Brown, Tom Holme

Publisher:Lawrence S. Brown, Tom Holme

Chapter10: Entropy And The Second Law Of Thermodynamics

Section: Chapter Questions

Problem 10.99PAE: Thermodynamics provides a way to interpret everyday occurrences. If you live in northern climates,...

See similar textbooks

Similar questions

What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the explosive decomposition of TNT? Use your knowledge of TNT and the chemical equation, particularly the phases, to answer this question. (Thermodynamic data for TNT are not in Appendix G.) 2C7H5N3O6(s) 3N2(g) + 5H2O() + 7C(s) + 7CO(g)
Another step in the metabolism of glucose, which occurs after the formation of glucose6-phosphate, is the conversion of fructose6-phosphate to fructose1,6-bisphosphate(bis meanstwo): Fructose6-phosphate(aq) + H2PO4(aq) fructose l,6-bisphosphate(aq) + H2O() + H+(aq) (a) This reaction has a Gibbs free energy change of +16.7 kJ/mol of fructose6-phosphate. Is it endergonic or exergonic? (b) Write the equation for the formation of 1 mol ADP fromATR for which rG = 30.5 kJ/mol. (c) Couple these two reactions to get an exergonic process;write its overall chemical equation, and calculate theGibbs free energy change.
Calculate the standard Gibbs free-energy change when SO3 forms from SO2 and O2 at 298 K. Why is sulfur trioxide an important substance to study? (Hint: What happens when it combines with water?)
Given the following information at 25C, calculate G at 25C for the reaction 2A(g)+B(g)3C(g) Substance Hf(kJ/mol) S(J/molK) A(g) 191 244 B(g) 70.8 300 C(g) 197 164 a 956 kJ b 956 kJ c 346 kJ d 346 kJ e 1.03 103 kJ
Thermodynamics provides a way to interpret everyday occurrences. If you live in northern climates, one common experience is that during early winter, snow falls but then melts when it hits the ground. Both the formation and the melting happen spontaneously. How can thermodynamics explain both of these seemingly opposed events?
For the reaction TiCl2(s) + Cl2(g) TiCl4(), rG = 272.8 kj/mol-txn. Using this value and other data available in Appendix L, calculate the value of fG for TiCl2(s).
Explain why the statement No process is 100 efficient is not the best statement of the second law of thermodynamics.
Reword the statement in Question 109 so that it is always true. Criticize this statement: Provided it occurs at an appreciable rate, any chemical reaction for which rG 0 will proceed until all reactants have been converted toproducts.
A reaction has H298=100 kj/mol and S298=250 J/mol K. Is the reaction spontaneous at room temperature? If not, under what temperature conditions will it become spontaneous?
Determine the standard Gibbs free energy change, rG, for the reactions of liquid methanol, of CO(g), and ofethyne, C2H2(g), with oxygen gas to form gaseous carbondioxide and (if hydrogen is present) liquid water at298 K. Use your calculations to decide which of thesesubstances are kinetically stable and which are thermodynamically stable: CH3OH(), CO(g), C2H9(g), CO2(g),H2O().
9.96 Most first aid "cold packs" are based on the endothermic dissolution of ammonium nitrate in water: NH4NO3(s)NH4+(aq)+NO3(aq) H= 25.69 kJ A particular cold pack contains 50.0 g of NH4NO3 and 125.0 g of water. When the pack is squeezed, the NH4NO3dissolves in the water. If the pack and its contents are initially at 24.0°C, what is the lowest temperature that this bag could reach? (Assume that the ammonium nitrate solution has a specific heat of 4.25J g-l K-l, and that the heat capacity of the bag itself is small enough to be neglected.)
The equilibrium constant for a certain reaction increases by a factor of 6.67 when the temperature is increased from 300.0 K to 350.0 K. Calculate the standard change in enthalpy (H) for this reaction (assuming H is temperature-independent).