CH301 Fall 2008 Worksheet 12 1. Assume we want to use a bomb calorimeter to determine the specific heat capacity of anunknown liquid. We use 3 L of the unkown liquid and perform a known reaction thatreleases 400 kJ of heat. We measure an initial and final temperature of 25 ºC and 28.7 ºC,respectively. If the heat capacity of the calorimeter is 85 J·K-1, and the density of the liquidis 2.34 g·mL-1, what is the specific heat capacity of the unknown liquid?2. Lets say we filled the calorimeter above with 3 L of water and performed the same knownreaction above. We measured a final temperature of 57.56 ºC, but forgot to measure theinital temperature. Considering the density and specific heat capacity of water are 1 g·mL-1and 4.184 J·g-1·K-1, could we calculate what the initial temperature must have been? If so,what was the initial temperature?3. Given the following data:P4(s) + 6Cl2(g) ↔ 4PCl3(g) ΔH = -1,225.6 kJ·mol-1P4(s) + 5O2(g) ↔ P4O10(s) ΔH = -2,967.3 kJ·mol-1PCl3(g) + Cl2(g) ↔ PCl5(g) ΔH = -84.2 kJ·mol-1PCl3(g) + 1/2O2(g) ↔ Cl3PO(g) ΔH = -285.7 kJ·mol-1calculate ΔH for the reactionP4O10(s) + 6PCl5(g) ↔ 10Cl3PO(g)4. Given the following data:2O3(g) ↔ 3O2(g) ΔH = -427 kJ·mol-1O2(g) ↔ 2O(g) ΔH = 495 kJ·mol-1NO(g) + O3(g) ↔ NO2(g) + O2(g) ΔH = -199 kJ·mol-1calculate ΔH for the reactionNO(g) + O(g) ↔ NO2(g)5. Hyrdoiodic acid (HI) and sodium hydroxide (NaOH) are a strong acid and strong baserespectively. Calculate the change in enthalpy for their neutralization reaction:HI(g) + NaOH(s) → NaI(s) and H2O(l)Consult Appendix 2 in your ebook for standard enthalpy of formation values.6. Calculate the change in enthalpy for the reaction of hydroxylamine and hydrogenperoxide to form ammonia, water and ozone.2NH2OH(s)2 + H2O2(aq) → 2NH3(aq) + H2O(l) + O3(g)Consult Appendix 2 in your ebook for standard enthalpy of formation values.7. Using bond enthalpies, approximate the change in enthalpy for the reaction in question 6above. Would the reaction be more or less endothermic with every species in the gasphase? Consult tables 6.7 and 6.8 in your ebook for mean bond enthalpies8. Calculate the change in standard molar entropy for the reaction in question 6 above.Consult Appendix 2 in your ebook for standard molar entropy values. Assume thathydroxyalmine has a standard molar entropy of 0. Also, discuss whether we areoverestimating or underestimating the change in standard molar entropy for the reaction .9. Based on the values of ΔHrxnand ΔSrxncalculated in question 6 and question 8, howwould the reactions spontaneity be effected by temperature? Explain your answer.10. Based on the values of ΔHrxnand ΔSrxncalculated in question 6 and question 8, at whattemperature would the reaction switch from being non-spontaneous to spontaneous. Inother words, what would T be if ΔGrxn= 0. Considering your answer to number 8, are weoverestimating or underestimating the temperature at which the reaction switches fromnon-spontaneous to spontaneous?11. In the list of elements below, mark (circle, underline, etc.) all of the elements that arenot shown in their standard state.Cdiamond(s) Ca(s) B2(s) Na(s) Fe(s) Hg(s)Br2(l) Mo(s) H(g) He(g) Xe(g) Rb2(s)Cd(l) As(s) N2(l) O2(l) Si60(s) F2(g)12. Write the standard formation reactions for the following chemical speciesNH3(g)Fe2O3(s)O2(l)O3(g)NH2OH(s)13. State in your own words the first law of thermodynamics. What are some of theconsequences of the first law?14. What is a state function? List all of the state functions you can.15. If we were harnessing a combustion reaction that produces lots of gaseous products todo work (like in a car's engine), how would lowering the temperature effect the amount ofwork we could do?Consider the following molecules for questions 16-20: O3, N2, CH4, SF616. Which has the fewest rotational modes? how many? why?17. Which has most vibrational modes? how many? why?18. Do any have more or less than 3 translational modes? why?19. Which has the most total modes? how many? why?20. Which has 9 vibrational
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