Ka for acetic acid, CH3COOH, is 1.80x10-5. Ka for hydrofluoric acid, HF, is 7.20×10-4. Ką for phenol (a weak acid), C6H5OH, is 1.60×10-10. What is the formula for the strongest conjugate base? CH₂OH

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Which of the following statements is the best explanation of how activation energy affects the rate of a chemical reaction?   A. A high activation energy means molecules have less kinetic energy and hence rate of reaction will be slower.   B. A high activation energy means molecules must have more kinetic energy to overcome it, and hence rate of reaction will be faster.   C. A high activation energy means molecules have a lot of kinetic energy and hence rate of reaction will be faster.     D. A high activation energy means molecules must have less kinetic energy to overcome it, and hence rate of reaction will be slower.   E. A high activation energy means molecules must have more kinetic energy to overcome it, and hence rate of reaction will be slower.

B. Rates of reaction are typically measured as the change of concentration per unit time. Some typical units of concentration are: M, mM, pM, µM, nM. Some typical units of time are: years, days, hr, s, ms, ps, µs, and ns. For each reaction, suggest a reasonable unit of measure for the rate of reaction. a. The combustion of gasoline. b. The transformation of organic material into crude oil. Chemical change involved with memory in the human brain. с. d. The rusting of an iron nail. 9. Why would a scientist use nM/ps instead of M/s? - 112 -