Question

Chemistry midterm help please! <3

7. What is the difference between the AU and AH of a reaction? A) AU is a state function, while AH is not a state function B) AH is a state function, while AU is not a state function. C) AU = heat of reaction at constant volume conditions; AH = heat of reaction at constant-pressure conditions D) AU is the heat of reaction, AH is the work done by the reaction E) AU = heat of reaction under standard state conditions, AH = heat of reaction under nonstandard state conditions. 8. Which one of the following processes has a A.S> 0? A) CH,OH () CH,OH (S) B) N2(g) + 3H2(g) - 2 NH3(g) C) CH,() + H2O() - CO(g) + 3H2(g) D) Na.CO,(s) +H-0 () + CO2(g) + NaHCO3(s) E) H:0(8) -H.0 (1) 9. For the reaction N2(g) +20,6) + 2 NO:(), AH = +66.4 kJ mor'. Determine Ascar for this reaction 298 K and constant pressure, and predict whether it will be spontaneous under these conditions. A) AS... = +223 J K mol', reaction is spontaneous B) AS -223 J K moll, reaction is not spontaneous C) AS..=-66.4 J K mol', reaction is spontaneous D) AS.... +66.4 J K mol', reaction is not spontaneous E) AS. = 66.4 J K mol'', reaction is not spontaneous 10. Consider a reaction that has a negative A, H and a positive A.S. Which statement is true? A) This reaction will be spontaneous only at high temperatures. B) This reaction will be spontaneous at all temperatures. C) This reaction will not be spontaneous at any temperature. D) This reaction will be spontaneous only at low temperatures E) This reaction will be spontaneous only at absolute zero (0 Kelvin). 11. Place the following: H2O(l), H,O (), H,0 (s), in order of standard molar entropy, from highest to lowest A) H20 (8) > H:0 (s) > H20 (1) B) H0g) +H0 (HO (8) C) H:0 (s) > H:0 (1) > H:0 (8) D) H:0 (5) > H:0 (g) > H20 (1) E) H0 (1) > 1,0 (s) >H.0 (8) 12. Calculate As for the following reaction. The S for each species is provided below. CH2(g) + 2 H2(g) - CH () A) +560.8 JK 'mor B) +303 3 J K mol SJK mor') C) -102.4 J K mol CH:() 200.9 D) -229.2 J K mot H ) 130.7 E) -233.1 J K'mol CH.) 229.2

Answer 1

a lodu is heat folletion at sukaut vcles Altis decat of ox" at constant presseuse 10 cry (9)+ H20lg2 - Colg) +3H219) AS 3(130-69) + (197-67) - 18.8.83-186 264 AS ZO Nalg)+2021g.) 3.21024) BHsys = 66.4 kJ/mol -__AS:_-547 Assum. = -66.4 kJ/mol _79814 - Reaction is not spontaneous 15--222.818 Imol-'k-/ (6) ofztion 10) M: A Legativen A Sa positie (W Reaction is spontaneous at - high temp temp 2293k) Hooll) = 69.91 H2o(g): 188.825 سه (s) a zlzs 12 ds 429.2 - 200.9-130.7 -- 102,4 kmon/