____ 2. What is the sequence of steps in a reaction called?
____ 3. Most steps in a reaction mechanism
____ 4. In the reaction represented by the following equation, a possible intermediate is H2(g) + I2(g) 2HI(g)
____ 5. Reactions whose reactants and products exist in a single phase are called
____ 6. To react, gas particles must
____ 7. To be effective, a collision requires
____ 8. Which attempts to explain chemical reactions and physical interactions of molecules?
____ 9. Raising the temperature of gas particles
____ 10. If a collision between molecules is very gentle, the molecules are
____ 11. The minimum energy required for an effective collision is called
____ 12. A short-lived structure formed during a collision is a(n)
____ 13. The bonding of the activated complex is characteristic of
____ 14. An activated complex
____ 15. In a diagram of an activated complex, broken lines represent
____ 16. What takes place in an activated complex?
____ 17. Raising the temperature of reactants in a system
____ 18. If a collision between molecules is oriented properly, the molecules are
____ 19. Which statement correctly describes the energy changes that occur when bonds form and when bonds break?
____ 20. is positive for
____ 21. Which term has the same numerical value for the forward reaction as it has for the reverse reaction but with opposite sign?
____ 22. Which of the following is true in an endothermic reaction?
____ 23. Which branch of chemistry studies reaction rates?
____ 24. Which branch of chemistry studies reaction mechanisms?
____ 25. The usual condition for reaction, a favorable orientation, is not necessary for
____ 26. How fast something changes with time is a(n)
____ 27. Reaction rate depends upon
____ 28. Which of the following affects reaction rate?
____ 29. The decrease in reactant concentration per unit time in a reaction is a measure of the
____ 30. If the surface area of reactants is larger,
____ 31. In heterogeneous reactions, the reactants
____ 32. If the temperature of the reactants is lower,
____ 33. Changing the pressure of a gas is another way of changing its
____ 34. Doubling the pressure of a gas
____ 35. Which process is used to speed up chemical reactions?
____ 36. Catalysts generally affect chemical reactions by
____ 37. A substance that slows down chemical processes is called a(n)
____ 38. How is a heterogeneous catalyst different from the reactants in a chemical reaction?
____ 39. In a net equation, catalysts
____ 40. A rate law relates
____ 41. The letter R in a rate law stands for
____ 42. The value of k in a rate law
____ 43. How are the units for a rate always expressed?
____ 44. In the rate law for the following equation, R=k[A]n[B]m, the units for [A] and [B] are
____ 45. In the rate law for the following equation, R=k[A]n[B]m, the unit for R is
____ 46. A reaction is zero order in reactant A and second order in reactant B. What happens to the reaction rate when the concentrations of both reactants are doubled?
____ 47. The rate law for a reaction generally depends most directly on the
____ 48. The rate for a reaction between reactants L, M, and N is proportional to the cube of [L] and the square of [M]. What is the rate law for this reaction?
____ 49. A transition structure that results from an effective energetic collision between reactants is the —
____ 50. How does the potential energy of the activated complex compare with the energies of the reactants and products?
____ 51. If a collision between molecules is very gentle, the molecules are —
____ 52. Which of the explanations below describes why catalysts can increase reaction rates?
____ 53. A rate law relates —
____ 54. A certain reaction is zero order in reactant A and second order in reactant B. What happens to the reaction rate when the concentrations of both reactants are doubled?