(Please indicate the solutions of the problems, only choosing the option will not be accepted!) 1) The thermal decomposition of acetaldehyde, CH CHO CH, +CO, is a second-order reaction. The following data were obtained at 518C. time. Pressure CH.CHO.mmg OL 42 105 720 364 330 290 Based on the data given, what is the half-life for the disappearance of acetaldehyde? A) 1.5 / 10's B) 410 C) 5.4 10's D) 520 s E) 305 s 2) The isomerization of cyclopropane follows first order kinetics. The rate constant at 700 K is 6.20 10-min', and the half-life at 760 K is 29.0 min. Calculate the activation energy for this reaction. A) 5.07 kJ/mol D) 60. kJ/mol B) 27.0 kJ/mol E) 270. kJ/mol C) 50.7 kJ/mol 3) At a particular temperature the first-order gas-phase reaction 2N,O, O 2N,0. +0. has a half-life for the disappearance of dinitrogen pentoxide of 3240 s. If 1.00 atm of N, O, is introduced into an evacuated 5.00 L flask, what will be the total pressure of the gases in the flask after 1.50 hours? A) 0.685 atm B) 100 atm C) 0.315 atm D) 1.68 atm E) 1.34 atm 4) For the reaction 2NOCI(S) 2NO(g) +CI(9), K = 8.0 at a certain temperature. What concentration of NOCI must dou that atm of N, O, is introduced into an evacuated 5.00 L flask, what will be the total pressure of the gases in the flask after 1.50 hours? A) 0.685 atm B) 1.00 atm C) 0.315 atm D) 1.68 atm E) 1.34 atm 4) For the reaction 2NOCKg) 2NO(g) + C1 (9), K = 8.0 at a certain temperature. What concentration of NOCI must be put into an empty 4.00 L reaction vessel in order that the equilibrium concentration of NOCI be 1.00 M? A) 1.26 MB) 2.25 M ) 2.50 M D) 3.52 M E) 11.0M 5) 50.0 g of N.0 is introduced into an evacuated 2.00 L vessel and allowed to come to equilibrium with its decomposition product, N.O.(g) 2NO(g). For this reaction K = 0.133. Once the system has reached equilibrium,5.00 g of NO, is injected into the vessel, and the system is allowed to equilibrate once again. Calculate the mass of NO, in the final equilibrium mixture. A) 17.8 g B) 12.4 g C) 14.7g D) 19.7g E) 15.5 g 6) 75.0 g of PCI;(g) is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250C. PC1 (g) PC12(g) + Cl (9) If K, = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium? A) 2.88 atm B) 2.27 atm C) 4.54 atm D) 7.42 atm E) 9.69 atm