CHEM 1220 - Practice Exam 1v1 - Exam

Question 1 A reaction with activation energy of 123 kJ/mol has a rate constant of 0.200 s at 38 o C. At what temperature will the rate constant be 0.400 s -1 ? 31 o C 43 o C 76 o C 225 o C 349 o C I am unsure and need to study this concept to prepare for the exam Question 2 The rate constant of a second-order reaction is 3.86 x 10 -2 M -1 s -1 . If the concentration of reactant A is 0.160 M after 75.6 sec, what was the initial concentration, [A] 0 ? (Assume the reaction is A → B + C) 0.300 M 0.325 M 1.50 M 2.96 M 3.08 M I am unsure and need to study this concept to prepare for the exam Question 3 A nonelectrolyte has the empirical formula C 3 H 9 Al. A solution of 0.144 g of the compound in 10.0 g of benzene (C 6 H 6 ) boils at 80.35 o C. The normal boiling point of benzene is 80.10 o C; the K is 2.53 o C/molal. What is the molecular formula of the compound? C 3 H 9 Al C 12 H 36 Al 4 C 6 H 18 Al 2 C 9 H 27 Al 3 I am unsure and need to study this concept to prepare for the exam Question 4 What is the concentration of a 1.570 x 10 -6 M aqueous solution of AgNO 3 expressed in parts-per-million (ppm)? Assume a density of 1.00 g/mL. (MM of AgNO = 169.88 g/mol) 1.57 ppm 1.57 x 10 -3 ppm 2.67 x 10 -1 ppm 2.67 x 10 2 ppm 9.24 x 10 -3 ppm I am unsure and need to study this concept to prepare for the exam

Question 5 In the collision model, which factor is most sensitive to changes in temperature? The fraction of molecules with energy greater than the activation energy. The frequency of collisions that occur between reactant molecules. The orientation factor for a given reactant molecule. The magnitude of the activation energy for a given reaction. I am unsure and need to study this concept to prepare for the exam Question 6 Which solute (listed first) would be the least soluble in the given solvent (listed second)? Na 2 CO 3 in C 6 H 12 CH 3 CN in C 2 H 5 OH HF in H 2 O Br 2 in CCl 4 KCl in H 2 O I am unsure and need to study this concept to prepare for the exam Question 7 Taking ion-pairing into account, which of the following solutions should have the smallest ΔTf? 0.10 m NaCl 0.10 m CaCl 2 0.10 m K 2 SO 4 0.10 m MgSO 4 I am unsure and need to study this concept to prepare for the exam Question 8 A student obtains the following plots from data collected in lab. Which rate law below is the most likely for the reaction? rate = k rate = k[A] rate = k[A] 2 rate = k[A] 1/2 rate = k[A] -1 I am unsure and need to study this concept to prepare for the exam