If A+B Products, and Rate= k[A][B]2 then:
The reaction is ____order with respect to A
The reaction is ____ order with respect to B
The reaction is ____ order overall
Give the equation and a linear graph for the following:
Zero order:
First order:
Second order:
The reaction SO2Cl2(g) SO2(g) + Cl2(g) is first order. Using the data below, determine the magnitude and units of the first order rate constant.
Time (s) / Pressure SO2Cl2 (atm)0 / 1.00
2500 / .947
5000 / .895
7500 / .848
10000 / .803
The decomposition of SO2Cl2 is first order.
a. At 600K the half-life is 2.3x105 s. What is the rate constant at this temperature?
b. At 320oC the rate constant is 2.2x10-5 s-1. What is the half-life at this temperature?
The decomposition of SO2Cl2 is first order.The rate of decomposition at 500K is 0.045s-1.
a. If the initial pressure is 450 torr, what is the pressure of the substance after 60s?
b. At what time will the pressure be 1/10 its original value?
The gas phase reaction Cl + HBrHCl + Br has an overall enthalpy change of -66 kJ. The activation energy for the reaction is 7 kJ.
a. Sketch the energy profile
b. What is the activation energy for the reverse product?
N2O5 decomposes into the solvent CCl4 as follows:
2 N2O5 4 NO2 + O2
The specific rate constant for the first-order decomposition at 45 oC is 6.32x10-4 s-1.
a. What is the concentration of N2O5 remaining after 2 hours if the initial concentration of N2O5 was 0.5M?
b. How much time is required for 90% of the N2O5 to decompose?
What is the molecularity of each of the following elementary reactions? Write the rate law for each.
a. Cl2 2Cl
b. OCl- + H2O HOCl + OH-
c. NO + Cl2 NOCl2
The following mechanism has been proposed for the gas phase reaction of H2 with ICl.
H2 + ICl HI + HCl
HI + ICl I2 + HCl
a. Write the balanced equation for the overall reaction.
b. Identify the intermediates, if any, for the reaction.
c. If the first step is slow and the second one fast, which rate law do you expect to be observed for the overall reaction?
Consider the following mechanism. A2 + B2 → R + C (slow)
A2 + R → C (fast)
a. Write the overall balanced chemical equation.
b. Identify the intermediates
c. What is the order with respect to each reactant?
d. Write the rate law for the overall reaction
Which of the following statements is typically true for a catalyst?
a. The concentration of the catalyst will go down as the reaction proceeds.
b. The catalyst provides a new pathway in the reaction mechanism.
c. The catalyst speeds up the reaction.
d. Two of the above.
e. None of the above
The catalyzed reaction has a _____ activation energy and thus causes a _____ reaction rate.
a. higher, lower
b. higher, higher
c. lower, higher
d. lower, steady
e. higher, steady
Determine which processes will be spontaneous:
a. Dissolving solid NaCl in water to form a solution
b. Decomposing CO2 into its elements at 25 oC and 1 atm
c. A ball rolling up a hill
d. Freezing of water at -3oC and 1 atm
Consider the reaction mechanism:
A + A X (fast)
X + B C + Y (slow)
Y + B D (fast)
a. Write the overall reaction
b. Name the intermediates
c. Write the rate law in terms of reactants and products.
Using the graph:
Consider the melting of 1 mol of ice, 7.5 kJ of energy is absorbed
H2O(s) H2O(l) is the system
a. Calculate S for the melting of 1 mol of ice at 0oC.
b. Calculate the Ssurr when the temperature is -100C.
c. Calculate the Suniv using parts A&B
d. Is the process spontaneous?
For each of the following pairs, which has the greater entropy?
a. CO2(s) or CO2(l)
b. NH3(l) or NH3(g)
c. A crystal of pure magnesium at 0K or 200K
Is the following reaction spontaneous at 25oC under the given conditions?
N2(g) + O2(g) 2NO(g) Nitrogen and oxygen gas have a pressure of 1 atm. Nitrogen oxide has a pressure of 4 atm. G0(rxn)= 173.1 kJ.
Are the substances in their standard state?
a. Al (s)
b. Fe (s) with some oxide impurity
c. H2 (g) at 2 atm
d. 1M solution of sugar in water
At 298 K, G0 =-190.5 kJ and H0 =-184.6 kJ for the reaction H2(g) + Cl2(g) 2HCl(g)
a. What is the standard entropy change for the reaction
Given the following data at 25 0C
S0 (J/mol-K) / Hf0 (kJ/mol)NO2(g) / 240.45 / 33.8
N2O4(g) / 304.33 / 9.66
a. Calculate the value of G0 of 2NO2(g) N2O4(g)
b. Is this spontaneous?
c. What is the value of the equilibrium constant for this reaction?
A catalyst increases the rate of a reaction by doing which of the following?
a. Increasing reactant concentrations
b. Increasing temperature
c. Decreasing temperature
d. Increasing activation energy of a reaction
e. Decreasing activation energy of a reaction
Given the following mechanism for a reaction:
Cl2(g) 2Cl(g)
2NO(g) + 2Cl(g) N2(g) + 2 ClO(g)
2ClO(g) Cl2(g) + O2(g)
Which of the following is a catalyst in the reaction?
a. Cl2
b. N2O5
c. N2
d. ClO
e. O2
What are the units of k for the rate law Rate=k[A][B]2 when the concentration unit is mol L-1?
a. s-1
b. s
c. L mol-1 s-1
d. L2 mol-2 s-1
e. L2 – s2 mol-2
The rate law for the reaction between NO(g) and H2(g) is rate=k[H2][NO]2.. Which statement is true based on the rate law?
a. NO(g) is consumed twice as fast as H2(g)
b. The rate-determining step involves a three-body collision
c. If the concentration of NO is doubled the rate doubles
d. The reaction is third order
e. The chemical reaction is H2(g) + 2NO(g) 2HO(g) + N2(g)
What is kp for the equilibrium H2(g) + I2(g) 2 HI(g) if G0 is -24.2 kJ at 490 0C?
a. 1.7
b. 2.6
c. 38
d. 46
e. 6600
What can we say about catalysts given the following information?
CO(g) + 3H2(g) CH4(g) + H2O(g)using Ni catalyst
CO(g) + 3H2(g) CH3OH(g)using ZnO/Cr2O3 catalyst
a. Catalysts are nonspecific in their activity
b. Catalysts are highly specific in their activity
c. Ni is a better catalyst than ZnO/Cr2O3
d. ZnO/Cr2O3 is a better catalyst than Ni
e. Most metals can act as a catalyst