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문제 1
An automotive fuel injector dispenses a fine spray of gasoline into the automobile cylinder, as shown in the bottom drawing here. When an injector gets clogged, as shown in the top drawing, the spray is not as fine or even and the performance of the car declines. How is this observation related to chemical kinetics? [Section 14.1]
- A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A(g) → B(g). The following data are collected: Time (s) 0 40 80 120 160 Moles of A 0.100 0.067 0.045 0.030 0.020 (a) Calculate the number of moles of B at each time in the table, assuming that A is cleanly converted to B with no intermediates.
문제 2
문제 2d
Consider the following graph of the concentration of a substance X over time. Is each of the following statements true or false? (d) As time progresses, the curve will eventually turn downward toward the x-axis. [Section 14.2]
문제 3a
You study the rate of a reaction, measuring both the concentration of the reactant and the concentration of the product as a function of time, and obtain the following results:
Which chemical equation is consistent with these data: (i) A → B, (ii) B → A, (iii) A → 2 B, (iv) B → 2 A?
문제 4b
Suppose that for the reaction K + L → M, you monitor the production of M over time, and then plot the following graph from your data:
(b) Is the reaction completed at t = 15 min? [Section 14.2]
문제 5
The following diagrams represent mixtures of NO(g) and O21g2. These two substances react as follows: 2 NO1g2 + O21g2¡2 NO21g2 It has been determined experimentally that the rate is second order in NO and first order in O2. Based on this fact, which of the following mixtures will have the fastest initial rate? [Section 14.3]
문제 7b
Given the following diagrams at t = 0 min and t = 30 min
After four half-life periods for a first-order reaction, what fraction of reactant remains? [Section 14.4]
- The addition of NO accelerates the decomposition of N2O, possibly by the following mechanism: NO(g) + N2O(g) ⟶ N2(g) + NO2(g) 2 NO2(g) ⟶ 2 NO(g) + O2(g). (c) If experiments show that during the decomposition of N2O, NO2 does not accumulate in measurable quantities, does this rule out the proposed mechanism?
문제 8
문제 8a
Which of the following linear plots do you expect for a reaction A¡products if the kinetics are (a) zero order, [Section 14.4]
![Four graphs showing plots of 1/[X], ln[X], and [X] over time for different reaction orders.](https://lightcat-files.s3.amazonaws.com/problem_images/fe3831e00d552752-1666282854514.jpg)
- Hydrogen sulfide (H2S) is a common and troublesome pollutant in industrial wastewaters. One way to remove H2S is to treat the water with chlorine, in which case the following reaction occurs: H2S(aq) + Cl2(aq) → S(s) + 2 H+(aq) + 2 Cl-(aq). The rate of this reaction is first order in each reactant. The rate constant for the disappearance of H2S at 28°C is 3.5 * 10^-2 M^-1 s^-1. If at a given time the concentration of H2S is 2.0 * 10^-4 M and that of Cl2 is 0.025 M, what is the rate of formation of Cl-?
문제 9
문제 10a
The accompanying graph shows plots of ln k versus 1>T for two different reactions. The plots have been extrapolated to the y-intercepts. Which reaction (red or blue) has (a) the larger value for Ea,
문제 10b
The accompanying graph shows plots of ln k versus 1>T for two different reactions. The plots have been extrapolated to the y-intercepts. Which reaction (red or blue) has (b) the larger value for the frequency factor, A? [Section 14.5]
문제 11b
The following graph shows two different reaction pathways for the same overall reaction at the same temperature. Is each of the following statements true or false? (b) For both paths, the rate of the reverse reaction is slower than the rate of the forward reaction.
문제 12d
Consider the diagram that follows, which represents two steps in an overall reaction. The red spheres are oxygen, the blue ones nitrogen, and the green ones fluorine. (d) Write the rate law for the overall reaction if the first step is the slow, rate-determining step. [Section 14.6]
문제 13
Based on the following reaction profile, how many intermediates are formed in the reaction A¡C? How many transition states are there? Which step, A¡B or B¡C, is the faster? For the reaction A¡C, is ΔE positive, negative, or zero? [Section 14.6]
- Draw a graph showing the reaction pathway for an overall exothermic reaction with two intermediates that are produced at different rates. On your graph, indicate the reactants, products, intermediates, transition states, and activation energies. [Sections 14.6 and 14.7]
문제 16
- (c) Is the rate of disappearance of reactants always the same as the rate of appearance of products?
문제 17
문제 17b
(b) Name three factors that can affect the rate of a chemical reaction.
문제 18a
(a) What are the units usually used to express the rates of reactions occurring in solution?
문제 18b
(b) As the temperature increases, does the reaction rate increase or decrease?
문제 18c
(c) As a reaction proceeds, does the instantaneous reaction rate increase or decrease?
문제 19a
Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected: Time (min) 0 10 20 30 40 Moles of A 0.065 0.051 0.042 0.036 0.031 (a) Calculate the number of moles of B at each time in the table, assuming that there are no molecules of B at time zero and that A cleanly converts to B with no intermediates.
문제 19b
Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected: Time (min) 0 10 20 30 40 Moles of A 0.065 0.051 0.042 0.036 0.031 (b) Calculate the average rate of disappearance of A for each 10-min interval in units of M>s.
문제 19c
Consider the following hypothetical aqueous reaction: A(aq) → B(aq). A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected: Time (min) 0 10 20 30 40 Moles of A 0.065 0.051 0.042 0.036 0.031 (c) Between t = 10 min and t = 30 min, what is the average rate of appearance of B in units of M/s? Assume that the volume of the solution is constant.
문제 20c
A flask is charged with 0.100 mol of A and allowed to react to form B according to the hypothetical gas-phase reaction A1g2¡B1g2. The following data are collected: Time (s) 0 40 80 120 160 Moles of A 0.100 0.067 0.045 0.030 0.020 (c) Which of the following would be needed to calculate the rate in units of concentration per time: (i) the pressure of the gas at each time, (ii) the volume of the reaction flask, (iii) the temperature, or (iv) the molecular weight of A?
문제 21a,c
The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215°C, and the following data were obtained:
Time (s) [CH3NC] (M)
0 0.0165
2000 0.0110
5000 0.00591
8000 0.00314
12,000 0.00137
15,000 0.00074
(a) Calculate the average rate of reaction, in M/s, for the time interval between each measurement. (c) Which is greater, the average rate between t = 2000 and t = 12,000 s, or between t = 8000 and t = 15,000 s?
문제 21b
The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215°C, and the following data were obtained:
Time (s) [CH3NC] (M)
0 0.0165
2000 0.0110
5000 0.00591
8000 0.00314
12,000 0.00137
15,000 0.00074
(b) Calculate the average rate of reaction over the entire time of the data from t = 0 to t = 15,000 s.
문제 21d
The isomerization of methyl isonitrile (CH3NC) to acetonitrile (CH3CN) was studied in the gas phase at 215°C, and the following data were obtained:
Time (s) [CH3NC] (M)
0 0.0165
2000 0.0110
5000 0.00591
8000 0.00314
12,000 0.00137
15,000 0.00074
(d) Graph [CH3NC] versus time and determine the instantaneous rates in M/s at t = 5000 s and t = 8000 s.
문제 22a
The rate of disappearance of HCl was measured for the following reaction: CH3OH1aq2 + HCl1aq2¡CH3Cl1aq2 + H2O1l2 The following data were collected: Time (min) 3HCl 4 1M2 0.0 1.85 54.0 1.58 107.0 1.36 215.0 1.02 430.0 0.580 (a) Calculate the average rate of reaction, in M>s, for the time interval between each measurement.
문제 22b
The rate of disappearance of HCl was measured for the following reaction: CH3OH1aq2 + HCl1aq2¡CH3Cl1aq2 + H2O1l2 The following data were collected: Time (min) 3HCl 4 1M2 0.0 1.85 54.0 1.58 107.0 1.36 215.0 1.02 430.0 0.580 (b) Calculate the average rate of reaction for the entire time for the data from t = 0.0 min to t = 430.0 min.