CHEM 3492 Chapter : Hw8

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azuremammoth471

15 Mar 2019

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Homework assignment 8 for chemistry 3492 (due on nov. 10) Non-graded problems: 20, 26 (in chapter 24), 2, 5, 11, 27, 29, 31 (in chapter 25) Graded problems: using the gibbs-duhem equation, please show for a binary solution: if p1 = x1p . 2 (0 x1 1) then p2 = x2p . 1 (0 x2 1): the addition of 100 g of a non-volatile unknown compound to 750 g ccl4 lowered the freezing point of the solvent by 10. 5 k at 1 atm. The normal freezing point of pure ccl4 is 250 k and the molar enthalpy of fusion is 2. 7 kj/mol. Calculate the molar mass of the compound: the boiling point of 0. 25-molal aqueous solution of mayer"s reagent, k2hgi4 is found to be. The normal boiling point of pure water is 100 c and the molar enthalpy of vaporization is 40. 7 kj/mol. Suggest a possible dissociation reaction that takes place when.

Related Questions

1. How many grams of calcium Chloride would be requird to be added to 500.0 grams of water to ensure the freezing point would be -2.5 degrees C? Given K_fim = ÎT

2. iff 222.8 grams of a non-volitile molecular compound lowers the vapor pressure of pure water by 3.0 mmHg when made into 375.0 grams of water. What would be the Molar Mass of the unknown compound given the vapor pressure of pure water at 30.0 degree C is 31.8 mmHg. (P(vapor pressure of solution)=X(mole fraction of solvent)P^{o(vapore pressure of pure solvent)})

3. Dr. Himes cut his finger on a nail and got sepsis meaning an infection began at the sight of the cut and traveled up his arm going to his heart. He had to go to the ER where they gave this 75 Kg professor 25 mm per Kg of his body mass of Vancomycin (C₆₆H₇₅Cl₂N₉O₂₄ MM = 1,449.3 g/mol). Please give the concentration of total Vancomycin in a 2.0 L IV bag in the terms below given the density is 10 g/mL.

Molarity________

Molality________

Mass Percent________

Mole Fraction_________

preparing for a test. please help. OMG omg

28. A milstion cossiding of a tion for all ef the following aguoou solutions hos ibe highest beeling penal (assume 100% disse D) 0.35m CJI,a E) 0 18m NaCi B) 0.10n AXND) 0.15m K.CO aqutres solution that is 51% urea by man? heon ofurea. CH.No, A) 038 B) 039 C) 053 D) 0.25 5 25, What is the mole molecular weight of a small proicis if a 0.26-g sample diswelvod in 146 ml of water bas an aanyk 26. Calculate lhe molecular weight of a small proteis ifa pressure or 9.8 mmilg at 25'C R-00211 mol B) 44 pmol E) 22 10 g/mol 4.4 10 mo The density of the soluton is lydoo aloric acid solinan? D) 636 m 27. What is the i molality of, 20 0% by mus 10380 g/ml A) B)S6Em C> 00220 m E) 5.02 m 0.200ç ceetaining carbon and nitroges has a composition of 46.16% carbon and 53.84% nitrogen A solution prepared by disclvingi so Eur this compound in, asooãtarinn, enchi ne, 28. A compound c by mass CCL, produces a solution thad boils 8004 C What is the molecalae formula of the compound? (Ke for that bailsé¸800r. What is the trolecular formula of te eompound? 4K, for CC1, is 5.0307m, and pure haa k treexing pint,of7672â) 29. A 3.140 molal solution of NaC i s prepared. How many grams of NaCI are present in a sample containing 1.577 kg of water? A) 49528 B) 84.7 g C) 1753 g D) 289 4S Eã none eethose 30. During osmosis A) pure solvent and a solution both diffuse at the same time through a membrane. B) pure solutes diffuse through a membrane but solvent does not C) gases diffuse theough a membrane into a solucion and build up pressure D) pure solvent diffuses through a membrane but solutes do sot 31. Whs is the molality of s solution ahat cntaine 71 3 g ofdice (CH.Cb) in 461 sl of carbon tetrachloride (CCl? The density of CCL is 1.60 /mL A) 0.658 m B) 168m C 0,097m D) 0.155 m E) 0.162m 32. .30g pl ora sene ua t isee of ae te ceas ing nob 0.89Â°C. What is the molar mass of the nonelectrolyte? (Kr for water is 1.858Â°C/m.) A) 1300 g/mol B) 210 gml C)2 260 pmol D) 100 gtmol E) 0.26 gmol 33. Wheti e aale fractioe of urea, COpi)h.in slsion pre0 g of urea in 320 a of methanol, CHOH? A) 092 B) 0.077 C)0.23 D) 0.86 E 0.14 84% sucrose (Ch10, 342 p mol) by mass cortains 1 1.0 g of What mass ofa solutioe labeled sucrose? A) 92g B) 130g C) 42g D) 23g E) 0.27 g 34.

Q1. Which of the following processes are spontaneous and which are non spontaneous.
a) The combustion of natural gas
b) Extraction of Aluminum metal from its ore
c) A ball rolling down a hill
d) A bike going up a hill

Q2. Predict the entropy change (positive or negative) for the following processes/reactions
a) a lake freezing
b) weeding a garden
c) N2(g) + 2 H2(g) ? N2H4 (g)
d) Mg(s) + 2H2O(l) ? Mg(OH)2 (s) + H2(g)

Q3. The element Cesium (Cs) freezes at 28.4 C and its molar enthalpy of fusion ΔH_fusion = 2.09 kJ/mol.
a) When molten Cs solidifies to Cs (s) at its normal melting point, is the entropy change ΔS positive or negative?
b) Calculate the entropy change S when 15.0 g of Cs(l) solidifies at 28.4 C.

Q4. Using the values for standard molar entropies ΔS_f° from the appendix in your textbook, calculate ΔS° for the following reactions.
a) Be(OH)₂ (s) ? BeO (s) + H2O (g)
b) Mg(OH)2 (s) + 2 HCl (g) ? MgCl2 (s) + 2H2O (l)
c) 2CH4(g) ? C2H6 (g) + H2(g)

Q5. Using the data in the appendix of your textbook, calculate the Gibbs free energy change ΔG° for the following reactions. In each case, indicate whether the reaction is spontaneous or not
a) H2 (g) + Cl2(g) ? 2HCl (g)
b) 2 POCl3 (g) ? 2 PCl3 (g) + O2 (g)

Q6. Consider the reaction 2 NO2 (g)---N2O4 (g)
a) Using the data in the appendix in your text, calculate the standard Gibbs free energy change (ΔG°) for the reaction at 298K.
b) For the above reaction, calculate the value of Keq at 298K
c) For the same reaction, calculate G at 298 K when the partial pressures for NO₂ and N2O4 are 0.40 atm and 0.36 atm, respectively.

Q7. Consider the reaction I2 (g) + Cl2 (g)----2 ICl (g) Kp = 81.9 at 298 K
a) Calculate the standard free energy change (ΔG°)
b) What will be the Free energy change when the above reaction is at equilibrium
c) Calculate G for the reaction at 298 K when PICl = 2.55 atm, PI2=0.325 atm and PCl2 = 0.221 atm

Q8. Consider the decomposition of Lead carbonate PbCO3 (s) ? PbO(s) + CO2 (g)
a) Calculate the Gibbs free energy change (ΔG°) for the reaction at298 K.
b) Calculate G for the reaction at 400 K.
c) Write down the equilibrium expression and calculate the value of Keq at 298 K
d) Calculate the partial pressure of CO2 at 298 K. (Hint: Look at the equilibrium expression and the value of Keq at 298 K)

Q9. For the reaction: 2Al(s) + 3/2 O2(g) ? Al2O3(s), ΔH^o_rxn = -1617 kJ/mol and ΔH^o_rxn = -1577 kJ/mol. Use this data to calculate ΔS^o_rxn reaction at 298 K.

Q10. Calculate the ΔG^o for the following reaction using the data from your text:
2SO2(g) + O2(g) ? 2SO3(g)

Q11. Using the thermodynamic data available from the Appendix(?Goâs), calculate ΔG^o rxn and calculate the equilibrium constant(K) for the reaction at 25 oC:
CaCO3(s) ? CaO(s) + CO2(g)

Q12. What is the minimum temperature required for the spontaneous conversion of CCl4(l) to CCl4(g) when ΔH°(vap) is 57.3 kJ/mol andΔS°(vap) is 164 J/(mol K)? reaction: CCl4(l) ? CCl4(g)

Q13. Given the following
Fe2O3(s) + 3CO(g) . ? 2Fe(s) + 3CO2(g) ΔG° = 29.4 kJ
3Fe2O3(s) + CO(g) . ? 2Fe3O4(s) + CO2(g) ΔG° = 61.6 kJ
Calculate ΔG° for Fe(s) + Fe2O3(s) + CO2(g) ? Fe3O4(s) +CO(g)

Q14. Calculate ΔG° rxn for 2CO(g) + O2(g) ? 2CO2(g) and then calculate ΔG for the reaction at 298K; if the pressure of CO =20. atm,P O2 = 10. atm and P CO2= 0.50 atm. Will increasing the pressure of the reactants make the reaction more or less spontaneous? Explain using your calculations and Le Chatelierâs principle.

Q15. Write the reaction for photosynthesis (production ofC6H12O6(s) and oxygen from carbon dioxide and water as a gas).Calculate ?H, ? S, and ?G for the reaction at standard state. Is the reaction spontaneous?

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CHEM 3492 Chapter : Hw8

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