1. A plot of \( \ln [A] \) vs time for a reaction is linear. What is the order of the reaction?

A. Zero order B. First order C. Second order D. Third order

2. What is the major difference between the integrated rate method and the inspection method for determining reaction order?

A. Integrated rate method is graphical; inspection method uses experimental data comparison B. Inspection method requires calculation of activation energy C. Integrated rate method applies only to zero-order reactions D. Both methods yield the same kinetic parameters

3. What units does a second-order rate constant have?

A. \( s^{-1} \) B. \( M^{-1}s^{-1} \) C. \( M s^{-1} \) D. Dimensionless

4. How can the half-life of a second-order reaction be expressed?

A. t½ = 0.693/k B. t½ = 1/(k[A]₀) C. t½ = k[A]₀ D. t½ = 1/k²

5. The rate law for a reaction is given by \( rate = k[A]^n \). What does the exponent \( n \) represent?

A. The number of reactant molecules B. The order of the reaction with respect to reactant \( A \) C. The activation energy of the reaction D. The total number of products formed

6. What does the rate of a chemical reaction represent?

A. The total mass of reactants B. The concentration of a product at equilibrium C. The change in concentration of reactant or product per unit time D. The time taken to complete the reaction

7. When plotting ln(k) against 1/T for a reaction, what does the slope of the line represent?

A. Activation energy divided by R B. Frequency factor C. Negative activation energy divided by R D. Reaction order

8. According to the Arrhenius equation, what effect does increasing temperature have on the rate constant, k?

A. It decreases k exponentially B. It has no effect on k C. It increases k exponentially D. It increases k linearly

9. If the rate constant doubles when the temperature is increased by 10 K, what is the approximate relationship between rate and temperature?

A. Rate halves every 10 K increase B. Rate doubles every 10 K increase C. Rate remains constant with temperature D. Rate increases by 100% every 5 K

10. Which of the following is TRUE about the rate constant \( k \)?

A. It changes with reactant concentration B. It is independent of temperature C. It has units depending on the order of the reaction D. It is always dimensionless

11. A reaction has a rate law \( rate = k[A]^m[B]^n \). What is the overall order of the reaction?

A. \( m \) only B. \( n \) only C. \( m \times n \) D. \( m + n \)

12. What does the rate constant (k) signify in the rate law equation rate = k[A]^n?

A. The initial concentration of reactant A B. The proportionality constant dependent on temperature C. The speed of product formation only D. The order of the reaction

13. In the Arrhenius equation k = Ae^(-Ea/RT), what is the physical meaning of the constant A?

A. Activation energy B. Collision frequency or frequency factor C. Gas constant D. Rate constant

14. Which method uses plotting \( \ln [A] \) versus time to determine the rate constant of a first-order reaction?

A. Initial rates method B. Rate curve method C. Integrated rate method D. Collision theory method

15. What is the effect of temperature on the rate constant \( k \)?

A. \( k \) decreases with increasing temperature B. \( k \) is independent of temperature C. \( k \) increases with increasing temperature D. \( k \) equals zero at high temperature

16. During a reaction where 74% of the starting material is converted, which expression correctly relates concentration at time t to the initial concentration for a first-order reaction?

A. [A]ₜ = 0.74 × [A]₀ B. [A]ₜ = 0.26 × [A]₀ C. [A]ₜ = [A]₀ / 0.74 D. [A]ₜ = [A]₀ × ln(0.74)

17. What is the overall order of a reaction with rate law \( rate = k[A]^2[B]^1 \)?

A. 1 B. 2 C. 3 D. 4

18. In kinetics, what does the term 'collision frequency' mean?

A. The total energy involved in the reaction B. The number of collisions per unit time that have enough energy to react C. The rate at which product molecules are formed D. The number of collisions per second regardless of energy

19. For a first-order reaction, how does the concentration of the reactant change with time?

A. Linearly increases B. Linearly decreases C. Exponentially decreases D. Exponentially increases

20. The Arrhenius equation relates rate constant \( k \) with:

A. Temperature and order of reaction B. Activation energy, frequency factor, temperature, and gas constant C. Rate and reactant concentration D. Half-life and initial concentration

21. How is the rate law determined experimentally?

A. By changing concentration of one reactant and keeping others constant B. Assuming reaction is zero order C. Measuring volume of products only D. By calculating molar masses

22. Which of the following is NOT a factor affecting the rate of a chemical reaction?

A. Concentration of reactants B. Temperature C. Presence of catalyst D. Shape of the container

23. If doubling \( [A] \) doubles the reaction rate, what is the order with respect to \( A \)?

A. 0 B. 1 C. 2 D. 3

24. Which of the following statements about molecularity is true?

A. It can have fractional values B. It is determined experimentally C. It is always a whole number D. It changes depending on temperature

25. The rate of a reaction is said to be zero order with respect to a reactant if:

A. The rate depends linearly on concentration of that reactant B. The rate does not change with concentration of that reactant C. The rate depends on the square of the reactant concentration D. The reactant is a catalyst

26. Which of the following affects the rate of reaction?

A. Concentration of reactants B. Temperature C. Presence of catalysts D. All of the above

27. Which of the following best describes the relationship between reaction rate and concentration in a zero-order reaction?

A. Rate is directly proportional to concentration of reactant B. Rate is independent of concentration of reactant C. Rate is proportional to square of concentration D. Rate decreases as concentration increases

28. What does the frequency factor \( A \) in the Arrhenius equation signify?

A. The rate constant B. The number of collisions per unit time that have correct orientation C. Activation energy D. Temperature

29. In the reaction of 2N2O5 → 4NO2 + O2, the rate doubles when the concentration of N2O5 is doubled. What is the order of reaction with respect to N2O5?

A. Zero order B. First order C. Second order D. Third order

30. In the reaction: 4NH3 + 5O2 → 4NO + 6H2O, how is the rate expression written in terms of disappearance of NH3?

A. rate = -1/4 d[NH3]/dt B. rate = -1/5 d[NH3]/dt C. rate = -4 d[NH3]/dt D. rate = d[NH3]/dt

31. In the equation \( \ln k = \ln A - \frac{E_a}{RT} \), what does the slope of a plot of \( \ln k \) vs \( 1/T \) represent?

A. \( \frac{E_a}{R} \) B. \( -\frac{E_a}{R} \) C. \( \ln A \) D. \( \frac{1}{RT} \)

32. Which order reaction has a rate independent of concentration?

A. Zero order B. First order C. Second order D. Third order

33. In the reaction \( 4NH_3 + 5O_2 \to 4NO + 6H_2O \), what is the rate expression in terms of disappearance of \( NH_3 \)?

A. \( rate = -\frac{1}{4} \frac{d[NH_3]}{dt} \) B. \( rate = -\frac{d[NH_3]}{dt} \) C. \( rate = -\frac{1}{5} \frac{d[O_2]}{dt} \) D. \( rate = \frac{d[NO]}{dt} \)

34. If a first-order reaction has a rate constant of 4.5 × 10^-4 s^-1 at 25°C, how does the rate constant at 50°C change, assuming Ea = 35.6 kJ/mol?

A. It halves B. It stays the same C. It approximately triples D. It decreases by 25%

35. Which method involves plotting ln(k) against 1/T to determine activation energy for a reaction?

A. Rate curve method B. Integrated rate method C. Arrhenius plot method D. Inspection method

36. For a first-order reaction, what is the relation between half-life (t½) and the rate constant (k)?

A. t½ = k B. t½ = 0.693/k C. t½ = k/0.693 D. t½ = 1/k²

37. What is the form of the Arrhenius equation?

A. \( k = Ae^{-\frac{E_a}{RT}} \) B. \( k = A + \frac{E_a}{RT} \) C. \( k = \frac{A}{RT} \) D. \( k = A \times E_a \times T \)

38. The molecularity of a reaction corresponds to:

A. The sum of orders of reaction B. Number of molecules involved in an elementary step C. Rate constant value D. The number of products formed

39. What is the unit of the rate constant \( k \) for a first-order reaction?

A. \( s^{-1} \) B. \( M \cdot s^{-1} \) C. \( M^{-1} \cdot s^{-1} \) D. Dimensionless

40. Which of the following best describes the activation energy in a chemical reaction?

A. The total energy released during the reaction B. The minimum energy required for a reaction to occur C. The heat absorbed by the system during reaction D. The frequency of collisions between reactant molecules

41. In a reaction where the rate is independent of reactant B concentration, what order is the reaction with respect to B?

A. Zero order B. First order C. Second order D. Fractional order

42. Which statement correctly distinguishes reaction order from molecularity?

A. Molecularity can be fractional; order is always a whole number B. Order is theoretical; molecularity is experimentally determined C. Order can change with reaction conditions; molecularity is invariant D. Molecularity is the sum of powers in the rate law; order is the number of reactants colliding

43. If the rate law for \( 2NO + O_2 \to 2NO_2 \) is \( rate = k[NO]^2[O_2] \), what is the order with respect to \( NO \)?

A. 0 B. 1 C. 2 D. 3

44. For a second-order reaction with rate law \( rate = k[A]^2 \), how does the half-life depend on the initial concentration \( [A]_0 \)?

A. \( t_{1/2} \) is independent of \( [A]_0 \) B. \( t_{1/2} = \frac{1}{k [A]_0} \) C. \( t_{1/2} = \frac{0.693}{k} \) D. \( t_{1/2} = k [A]_0 \)

45. What is the activation energy \( E_a \) in a chemical reaction?

A. The energy released on product formation B. The minimum energy required for effective collision leading to reaction C. The total energy change during reaction D. The maximum energy of products

46. According to collision theory, a reaction occurs if colliding molecules possess:

A. Zero kinetic energy B. Energy less than activation energy C. Sufficient kinetic energy equal or greater than activation energy D. Any amount of kinetic energy regardless of value

47. How does the rate of a reaction typically change when the concentration of its reactant is doubled for a second-order reaction?

A. It remains unchanged B. It doubles C. It quadruples D. It halves

48. The half-life \( t_{1/2} \) of a first-order reaction is given by which formula?

A. \( t_{1/2} = \frac{1}{k} \) B. \( t_{1/2} = \frac{0.693}{k} \) C. \( t_{1/2} = k \times [A]_0 \) D. \( t_{1/2} = \frac{[A]_0}{k} \)

49. The rate law for the reaction 2NO + 2H2 → N2 + 2H2O was experimentally found to be rate = k[NO]^2[H2]. What is the overall order of this reaction?

A. 1 B. 2 C. 3 D. 4

50. What is the integrated rate law for a zero-order reaction?

A. \( [A]_t = [A]_0 - kt \) B. \( \ln [A]_t = \ln [A]_0 - kt \) C. \( \frac{1}{[A]_t} = \frac{1}{[A]_0} + kt \) D. \( [A]_t = [A]_0 e^{-kt} \)