The photoelectric work function of potassium is 2.3eV. If light with wavelength 250nm falls on potassium find (a) the stopping potential in volts. (b) the kinetic energy in eV of the most energetic electron ejected (c)the speed of these electrons (d)If potassium is replaced with Aluminium, which has a greater work function (4.3eV), compute the change in the threshold frequency.
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4.)Sketch a potential energy diagram for the endothermic, elementary reaction
A + B à C + D
and on it denote the activation energies, heat of reaction.Also indicate the reactants, products transition state.
5.)Explain collision theory?
6.)Explain why all reactions have an activation energy, using your knowledge of collision theory
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1. Calculate the concentration of the lactate ion in a solution that is 0.100 M in lactic acid (CH3CH(OH)COOH, pKa = 3.86) and 0.080 M in HCl.
2. For the generic equilibrium HA(aq) ⇌ H+(aq) + A−(aq), which of these statements is true?
| If you add the soluble salt KA to a solution of HA that is at equilibrium, the pH would increase. | |
| If you add the soluble salt KA to a solution of HA that is at equilibrium, the concentration of A− would decrease. | |
| The equilibrium constant for this reaction changes as the pH changes. | |
| If you add the soluble salt KA to a solution of HA that is at equilibrium, the concentration of HA would decrease. |
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What in ideal mixture? How does it differ from an ideal gas mixture? What about an ideal-dilute solution?
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I mix together 50.0 mL of 0.100 M NaIO3, 50.00 mL of 0.100 M NaOH, and 10.0 mL of 0.100 M HIO3. What is the pH of the mixture?
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1. How does temperature affect solubility of salicylic acid based on your results?
2. Explain how you used Beer
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How do you find the rate constant here?
| trials | [I] | [H2O2] | [H] | temp (C) | Rate (M/s) |
| 1 | 8.53*10^-3 | 1.03*10^-1 | 0.333 | 21.5 | 5.33*10^-4 |
| 2 | 8.53*10^-3 | 1.03*10^-1 | 0.333 | 15 | 4.3*10^-4 |
| 3 | 8.53*10^-3 | 1.03*10^-1 | 0.333 | 42 | 2.17*10^-3 |
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|
Identify the oxidizing agent and the reducing agent in the
following: answer is
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||
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How many grams of oxygen does it take to burn 16.8 g of glucose?
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Complete and balance the following equations, and identify the oxidizing and reducing agents. (Use the lowest possible coefficients. Include states-of-matter (s), (l), (g), (aq) similar to the given reaction.)
1.
(a) Tl2O3(s) + NH2OH(aq) ? TlOH(s) + N2(g) (basic solution)
(b)What is the oxidixing agent?
2.
(a) I2(s) + OCl-(aq) ? IO3-(aq) + Cl-(aq) (acidic solution)
(b) What is the oxidizing agent?
(c) What is the reducing agent?
3.
(a) MnO4-(aq) + Cl-(aq) ? Mn2+(aq) + Cl2(g) (acidic solution)
(b) Reducing agent?
4.
(a) H2O2(aq) + Cl2O7(aq) ? ClO2-(aq) + O2(g) (basic solution)
(b) Oxidizing agent?
(c) Reducing agent?
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Consider the titration of 30.0ml of 0.030 M NH3 (Kb=1.8 x 10^-5) with 0.025M HCl. What is the pH after the addition of 36.0mL of HCl?
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Styrene is polymerized by free radical mechanism in solution. The initial monomer and initiator concentrations are 1 M and 0.001 M, respectively. At the polymerization temperature of 60ºC, the initiator efficiency is 0.30. The rate constants at the polymerization temperature are as follows:
kd= 1.2 x 10-5 s-1
kp= 176 M-1s-1
kt= 7.2 107m-1s-1
Given this information, determine the following;
a. Rate of initiation at 1 min and at 16.6 hrs
b. Steady-state free radical concentration at 1 min
c. Rate of polymerization at 1 min
d.Average free-radical lifetime, t,at 1 min, where t is defined as the radical
concentration divided by the rate of termination.
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1) Determine how the following error would affect calculated the percent yield of alum. (increase, decrease, no effect). Briefly explain.
- Alum Sample was not dried completely in the oven.
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Describe the following techniques (Fourier transform spectroscopy):
a. Michelson interferometer
b. Diffuse reflectance
c. Attenuated total reflectance method
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Assign oxidation states to each atom in each of the following species.
Part A
N2
Part C
HgS
Part D
CH4
Part E
Cr2O72?
Part F
HCO3?
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