Physical Chemistry Multi-Choice Midterm 2 with Formula Sheet | CHEM 4373, Exams of Physical Chemistry

Download Physical Chemistry Multi-Choice Midterm 2 with Formula Sheet | CHEM 4373 and more Exams Physical Chemistry in PDF only on Docsity! Midterm # 2, Tnstructor: 6 questions of equal value) Instructions: First, bubble in your name and Peoplesoft ID number on the scantron forms provided, using #2 pencil. Next, write your name on top of this page. AI problems are multiple choice. For each question, &ll in the bubble corresponding to your answer ou the scantron form provided. Entries with more than one filled bubble will be disqualified. No partial credit will be assigned for questions. ‘There is no additional penalty for incorrect answers, and so it is in your interest to answer all questions. Look through all problems frst! Formula Sheet: ‘Lhe universal gas coustant: M xing entropy: AS = —Nkylcna+ (1-2) n(t—2)] dB = Td8 —palV + dN dH = TdS+Vdp+pdN dG = Sut 1 Vdp + pd oe @ = aN G = H-1S AG = STH A;Gh, for reaction S“ Ai = 0 Clausius-Clapeyron: dp A dT ~ TAY Fequiparcition: Equilibrium « Tdeal gas law: Work done by a enfant etl as gael In(ey) = a(x) +ta(y) 1. Suppose yon have used the equation of state for the ideal gas to estimate the pressure of a real gas: and, as a result, obtained a figure that is lower than the actual pressure. The cause of the discrepancy is that at the conditions in question, (a} the molecules attract (b} the molecules do not interact, (c) whe molecules repel (d) not enough information 2. The speci ¢ heat of melting of ice is 334 kJ/kg. he amount of heat needed to melt 1 mole of ici (a) 3.3 kd (b) 6.0 kJ (c) -3.3 kJ (d) - 6.0 kd 3. According to the Gibbs £ cnorgy dependence on an order parameter below, G (a) State 1 corresponds 4o stable equitibrinm A (b) State 2 corresponds to neutral equilibrium | 4 {c) State 3 corresponds to metastable equilibrium | i {d) none of the above ne 10. ‘Lhe formation enthalpies of A, B, and AjBy are: Ags =0 kJ/mol, Ay Hy = 20 kJ/mol, Ap l's,u = —300 kJ/mol. The reaction enthalpy of the reaction sA+ 3B = $AaBy ist (a) ~ 360 kJ/mol (b) -60 kJ/mol (c) 360 kJ/mol (4) 60 kJ/mol LL. [fin the reaction entropy in ube preceding exercise is -600 J/K/mol, and assumiug the reaction entropy and cuthalpy are temperature independent, the reaction (a) will proceed as written above 100 kk (b [e) ‘will proceed as written below 100 kK will proceed as writen above 600 K (d) will proceed as written below 600 K 12, From the information LOL) + Og(y) + BH2O2() AH = 196.1kJ | H20( > Hala) + 502 AH = 285.8k) the cuthalpy change for the reaction 2Hy(g) | Og(g) + 2H202{2) is {a) 1187.8 kJ (b) 189.7 kl {¢) -187.8kI (a) -875.5 kJ  13. ‘The standard Gibbs free energy of the reactions (1) A+B 2 kJ/mol respectively, at ‘f= 3004. It is true that AB and (2) A+ = AC are -| kJ/mol aud (a) the ratio of the equilibrium constants is Ky/ Ky = 4.1078 (b} the ratio of the equilibrium constants is Ky/Ky = 2.2-10* (c} the ratio of the equilibrinm constants is Ky/ A, = 3.3 (d) the ratio of the equilibrium constants is K2/A) = 0.33 14. Based on your knowledge of intensive vs. extensive variables and the number of independent, iuteusive variable in a one-component systom {or your knowledge of increments of thermodynamic potentials), the following statcment. is correct + (a) pdN = Sd + Vap (b) Nd = —Sdl + Vdp (©) Ndp = TdS ~ pdv (d) pdN = Tas — pav 18, Consider an ideal gas within a container. Upon increasing the concentration of the gas by a factor of two, while keeping the temperature constant: (a) The pressure will inerease by a [actor of two, average speed will increase by a factor of two (b) The pressure will uot change, average speed wil! increase by a factor of two (c) The pressure will increase by a factor of two, average speed will increase by a factor of /2 (d) The pressure will increase by a factor of two, average speed will not change 6 16. Which graph most closely resembles the molecular speed distribution for ie and Ar? 1 ’ a AY