Concept explainers
Are the following processes examples of homogeneous or heterogeneous catalysis? (a) Hydrolysis of immiscible ethyl acetate
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Physical Chemistry
- In a study of the formation of HI from its elements, H2(g) + 12(g) == 2HI(g) equal amounts of H2 and 12 were placed in a container, which was then sealed and heated. (a) On one set of axes, sketch concentration vs. time curves for H and HI, and explain how Q changes as a function of time. (b) Is the value of Q different if [12] is plotted instead of [H2]?arrow_forwardThe maximum rate I at which oxygen molecules can be consumed by a bacterium or radius R in a lake where the concentration of oxygen is co = 0.2 mole m³ increases with the first power of R. We might expect the oxygen consumption, however, to increase roughly with an organism's volume. Together, this statements imply an upper limit to the size of a bacterium: If R gets too large, the bacterium would literally suffocate. The actual metabolic activity of a bacterium is about 0.02 mole kg-' sl. What limit do you then get on the size R of a bacterium? Compare to the size of a real bacteria. Can you think of some way for a bacterium to evade this limit?arrow_forwardFor which reaction below would you expect to have the largest orientation factor (p)?(a) N2(g) + 3 H2(g) → 2 NH3(g)(b) O3(g) + O(g) → 2 O2(g)(c) CH3OH(l) + HCl(g) → CH3Cl(l) + H2O(l)(d) 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)arrow_forward
- Consider the following gas phase reaction at constant volume: 2CH2N2(g) −→ 2N2(g) + C2H4(g) i) Given that the initial pressure is p0 calculate the total pressure after three quarters of the CH2N2(g) has reacted. ii) Derive an equation which shows how the total pressure varies as a function of the fraction, α, of the CH2N2(g) that has reacted. iii) Sketch a graph which shows how the pressure varies as a function of αarrow_forwardAssume that the formation of nitrogen dioxide: 2NO(g) + O2(g) 2NO2(g) is an elementary reaction. (a) Write the rate law for this reaction. (b) A sample of air at a certain temperature is contaminated with 2.0 ppm of NO by volume. Under these conditions, can the rate law be simplified? If so, write the simplified rate law. (c) Under the conditions described in part (b), the half-life of the reaction has been estimated to be 6.4 × 103 min. What would the half-life be if the initial concentration of NO were 10 ppm?arrow_forwardPeroxynitric acid (HOONO2) is an unstable molecule that decomposes to nitric acid and oxygen: 2HOONO2(aq) → 2HNO3(aq) + O2(g)When the concentration of peroxynitic acid is graphed against time, the resulting plot is curved, but if the logarithm of this concentration is plotted, we instead get a straight line. Based on this, which statement is true? a) This decay is a second order in peroxynitric acid. b) The slope of the straight-line graph is the rate constant. c) One needs the concentration of peroxynitric acid to calculate its half-life. d) The rate law appears to be of the form -Δ[HOONO2]/Δt = k[HOONO2].arrow_forward
- The first step in the heterogeneoushydrogenation of ethylene is adsorption of theethylene molecule on a metal surface. One proposed explanation for the “sticking” of ethylene to a metalsurface is the interaction of the electrons in the C—C π bond with vacant orbitals on the metal surface. (a) If thisnotion is correct, would ethane be expected to adsorb to a metal surface, and, if so, how strongly would ethane bindcompared to ethylene? (b) Based on its Lewis structure,would you expect ammonia to adsorb to a metal surfaceusing a similar explanation as for ethylene?arrow_forwardHere is the correct statement for Qc and Kc for a certain reaction. Qc value is determined by the concentrations of reactants and products at a particular moment rather than by the temperature, but Kc value stays the same at a certain temperature regardless of the concentrations. For the following reaction at 20oC, the Qc value at a particular time is equal to 3.5 x 10‒5 3A(aq) + B(aq) ⟶ 2C(aq) + D(aq) Kc = 5.5 x 10‒5 If the reaction temperature is suddenly increased to 40oC without affecting the concentration of each component in the system, which of the following is a correct prediction about Qc and Kc at this particular time at 40oC? Q ≠ 3.5 x 10‒5, K = 5.5 x 10‒5 Q ≠ 3.5 x 10‒5, K ≠ 5.5 x 10‒5 Q = 3.5 x 10‒5, K ≠ 5.5 x 10‒5arrow_forward(a) The decomposition of a gas phase reactant, A, into gaseous products, P and Q, proceeds according to the reaction stoichiometry: A (g) P (g) + Q (g) and has been studied by measurement of the pressure increase in a constant volume system. Starting with an initial pressure of 112 torr of pure A at 713 K, the following total pressures, were measured at the times stated: Time (min) Pressure (Torr) | 136 15 30 45 60 75 155 170 181 191 (i) Give a suitable expression for the integrated rate equation by which the tabulated data can be analysed to confirm that the reaction exhibits first order kinetics. (ii) Calculate the rate constant and the half life of the reaction. (ii) If the activation energy of the reaction is given by 120 kJ mol, determine the rate constant and half life at a temperature of 1100 K.arrow_forward
- In the laboratory, hydrogen gas of good purity can most easily be obtained by the reaction of a strong acid, like sulfuric acid, on a reactive metal, such as zinc: Zn(s)+H,SO,(uq) - ZnS0, (ag) +H,{g) Suppose an engineer decides to study the rate of this reaction. He prepares four reaction vessels by adding 131.1 g of solid zinc and 74. mL of 5.0 M sulfuric acid solution to each, and then filling the remainder of the vessel with distilled water. The volume and temperature of each vessel is shown in the table below. Arrange the reaction vessels in decreasing order of initial rate of reaction. In other words, select a "1" next to the vessel in which the engineer can reasonably expect the initial rate of reaction to be highest, a "2" next to the vessel in which the initial rate of reaction would be next highest, and so on. Initial rate of reaction vessel volume temperature S0L 20 °C 5.0L -2,0 °C 50L 0°C 50L -3.0°Carrow_forward8 Reactions between certain organic (alkyl) halides and water produce alcohols. Consider the overall reaction for t-butyl bromide (2-bromo-2-methylpropane). (CH3)3CBr(aq) + H2O(1) →(CH3)3COH(aq) + H*(aq) + Br "(ag) k[(CH3)3CB1]. The accepted mechanism for the The experimental rate law is rate = %3D reaction is shown below. (1) (CH3)3C-Br(aq) →(CH3)3C*(aq) + Br "(aq) [slow] (2) (CH3)3C*(aq) + H2O(1) →(CH3)3C-OH2*(aq) [fast] (3) (CH3)3C-OH2*(aq) →H*(aq) + (CH3)3C-OH(aq) [fast] a) Why doesn't H2O appear in the rate law? b) Write rate laws for the elementary steps. c) What intermediates appear in the mechanism? d) Show that the mechanism is consistent with the experimental rate law. ed to the of consumption of Narrow_forwardhello, i sent this question before but the answer you rpovided for both wasnt right and i couldnt undertstand how you got the answer. can you please show me a handwritten solution for better understanding. 1a) The decomposition of ethanol at some constant temperature (above 500°C), over a copper surface, C2H5OH(g) CH3CHO(g) + H2(g) was studied by monitoring the total pressure with time.The following data were obtained: t (s) Ptotal (torr) 0 120 45 131 139 154 233 177 376 212 380 213 What will be the total pressure at t = 462 s? 1b) What is the rate constant (k)?(Include appropriate units.)arrow_forward
- Chemistry for Engineering StudentsChemistryISBN:9781337398909Author:Lawrence S. Brown, Tom HolmePublisher:Cengage Learning