MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. ) The half-life of a first-order reaction. A) can be calculated from the reaction rate constant B) is constant C) does not depend on the initial reactant concentration D) is the time necessary for the reactant concentration to drop to half its original value E) All of the above are correct. 2) The mechanism for formation of the product X is: A + B C + D B + D X (slow) (fast) The intermediate reactant in the reaction is. A) A B) B C) C D) D E) X 3) A solution contains 28% phosphoric acid by mass. This means that. A) L of this solution has a mass of 28 g B) L of this solution contains 28 ml of phosphoric acid C) ml of this solution contains 28 g of phosphoric acid D) the density of this solution is 2.8 g/ml E) 00 g of this solution contains 28 g of phosphoric acid 4) Which one of the following substances is more likely to dissolve in CCl4? A) CBr4 B) NaCl C) CH3CH2OH D) HBr E) HCl 5) The rate of a reaction depends on. A) collision frequency B) collision orientation C) collision energy D) all of the above E) none of the above 6) Colligative properties of solutions include all of the following except. A) elevation of the boiling point of a solution upon addition of a solute to a solvent B) depression of the freezing point of a solution upon addition of a solute to a solvent C) an increase in the osmotic pressure of a solution upon the addition of more solute D) the increase of reaction rates with increase in temperature E) depression of vapor pressure upon addition of a solute to a solvent

2 7) For the elementary reaction NO3 + CO NO2 + CO2 the molecularity of the reaction is, and the rate law is rate =. A) 4, k[no3][co][no2][co2] B) 2, k[no3][co] C) 2, k[no2][co2] D) 2, k[no3][co]/[no2][co2] E) 4, k[no2][co2]/[no3][co] 8) The concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in 200 g of C2H6O is M. The density of the solution is 0.79 g/ml. A) 0.93 B) 2 C) 0.58 D).72 E) 6.0 x 0-4 9) Hydration is a specific example of the phenomenon known generally as. A) solvation B) disordering C) salutation D) dilution E) condensation 0) Which of the following aqueous solutions will have the highest boiling point? A) 0.0 m Na2SO4 B) 0.20 m glucose C) 0.0 m NaCl D) 0.0 m SrSO4 E) 0.25 m sucrose ) Which one of the following concentration units varies with temperature? A) mole fraction B) mass percent C) molarity D) molality E) all of the above 2) Of the following, all are valid units for a reaction rate except. A) mol/hr B) mol/l C) mol/l-hr D) M/s E) g/s 2

3 3) Which energy difference in the energy profile below corresponds to the activation energy for the forward reaction? A) x B) y C) y - x D) x + y E) x - y 4) The rate law of the overall reaction A + B C is rate = k[a]2. Which of the following will not increase the rate of the reaction? A) increasing the concentration of reactant B B) increasing the temperature of the reaction C) adding a catalyst for the reaction D) increasing the concentration of reactant A E) All of these will increase the rate. 5) The concentration of nitrate ion in a solution that contains M aluminum nitrate is M. A) B).80 C) D) 2.70 E) ) The concentration of nitrogen in water is M when the partial pressure of N2 above the solution is atm. Henry's Law constant for this system is 6.8 x 0-4 mol/l-atm. A).2 x 03 B) 5.6 C) 0.43 D) 8.2 x 0-3 E) 5.6 x 0-4 7) In the energy profile of a reaction, the species that exists at the maximum on the curve is called the. A) product B) enthalpy of reaction C) activated complex D) atomic state E) activation energy 8) The magnitudes of Kf and of Kb depend on the identity of the. A) solvent and on temperature B) solute and solvent C) solute D) solution E) solvent 3

4 9) Which of the following liquids will have the lowest freezing point? A) pure H2O B) aqueous KF (0.50 m) C) aqueous FeI3 (0.24 m) D) aqueous glucose (0.60 m) E) aqueous sucrose (0.60 m) 20) The ideal value of i (van't Hoff factor) for (NH4)3PO4. A) 2 B) 5 C) 4 D) 3 E) 2) Pressure has an appreciable effect on the solubility of in liquids. A) salts B) gases C) solids and liquids D) solids E) liquids 22) After swimming in the ocean for several hours, swimmers noticed that their fingers appeared to be very wrinkled. This is an indication that seawater is relative to the fluid in cells. A) hypertonic B) isotonic C) hypotonic D) none of the above E) supertonic 23) For a first-order reaction, a plot of versus is linear. A) ln [A]t, t B) [A]t, t C) t, D) In [A]t, [A]t t E) [A]t, t 24) The graph shown below depicts the relationship between concentration and time for the following chemical reaction. The slope of this line is equal to. A) -/k B) k C) ln[a]o D) -k E) /k 4

5 25) Adding solute to a solution decreases the of the solution. A) boiling point B) vapor pressure C) freezing point and vapor pressure D) osmotic pressure E) freezing point 26) In the Arrhenius equation, k = Ae-Ea/RT is the frequency factor. A) e B) Ea C) R D) k E) A 27) The mole fraction of urea (MW = 60.0 g/mol) in a solution prepared by dissolving 6 g of urea in 39 g of H2O is. A) 0. B) 0.58 C) 0.37 D) 0.3 E) 9. 28) If the rate law for the reaction 2A + 3B products is first order in A and second order in B, then the rate law is rate =. A) k[a]2[b] B) k[a]2[b]3 C) k[a]2[b]2 D) k[a][b] E) k[a][b]2 29) A solution is prepared by dissolving 5.0 g of NH3 in 250 g of water. The density of the resulting solution is g/ml. The mole fraction of NH3 in the solution is. A) 6.8 B) C) D) E) ) At elevated temperatures, dinitrogen pentoxide decomposes to nitrogen dioxide and oxygen: 2N2O5(g) 4NO2 (g) + O2 (g) When the rate of formation of NO2 is M/s, the rate of decomposition of N2O5 is M/s. A) B) C) D) E) ) The concentration of KBr in a solution prepared by dissolving 2.2 g of KBr in 897 g of water is molal. A) B) C) 2.07 x 0-5 D) 2.46 E)

6 32) A burning splint will burn more vigorously in pure oxygen than in air because A) nitrogen is a product of combustion and the system reaches equilibrium at a lower temperature. B) oxygen is a reactant in combustion and the concentration of oxygen is higher in pure oxygen than it is in air. C) nitrogen is a reactant in combustion and its low concentration in pure oxygen catalyzes the combustion. D) oxygen is a catalyst for combustion. E) oxygen is a product of combustion. 33) The process of a substance sticking to the surface of another is called A) adsorption B) coagulation C) diffusion D) absorption E) effusion 34) The phenomenon used to differentiate colloids and true solutions is called the effect. A) van't Hoff B) Henry C) Osmotic D) Tyndall E) Raoult 35) Pairs of liquids that will mix in all proportions are called liquids. A) saturated B) supersaturated C) miserable D) miscible E) polar liquids 36) The process of solute particles being surrounded by solvent particles is known as. A) salutation B) agglutination C) dehydration D) agglomeration E) solvation 37) A second-order reaction has a half-life of 8 s when the initial concentration of reactant is 0.7 M. The rate constant for this reaction is M-s-. A) 3.8 x 0-2 B) 7.8 x 0-2 C) 8 D).3 E) 2.0 x 0-2 6

7 Answer Key Testname: 42-F.TST MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. ) E 2) D 3) E 4) A 5) D 6) D 7) B 8) C 9) A 0) A ) C 2) B 3) A 4) A 5) D 6) E 7) C 8) E 9) B 20) C 2) B 22) A 23) A 24) D 25) C 26) E 27) A 28) E 29) C 30) A 3) B 32) B 33) A 34) D 35) D 36) E 37) B