CHEM-6 Midterm: Chem 6 Dartmouth Spring Exam 1S

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turquoisegnu128

31 Jan 2019

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Sample exam 1 solutions: (a) to find the reaction orders, look at the dependence of rate on concentrations. From rows 1 and 3, cutting the [ocl ] in half cuts the rate in half, so the reaction is 1st order in ocl . Similarly, from rows 2 and 3, cutting the [i ] in half cuts the rate in half, so it"s also first order in i . To find the rate constant k, plug in some data. From row 1, for example, rate = 4. 8x10 4ms 1 = k [0. 0040m] [0. 0020m]/[1. 00m] k = 60s 1: note for 2003, 2004, 2005, etc. If you found this one difficult, don"t worry too muchwe have not looked at similar "pressure" problems this year. First define p = total pressure, po = initial pressure of c2h4o, pa = pressure of. C2h4o, pb = pc = pressure of ch4 = pressure of co, and x = number of moles of.

Related Questions

1. 30 Points) The stability of a pharmaceutical product has been studied at standard temperature and pressure. The activity of the drug was determined at 10-day intervals, and the concentrations in Î¼Units/mL determined in this study are: 10, 6.86, 5.20, 4.15, and 3.45. a)Find the order of the reaction.

b)Determine the rate constant (k), with units, for this reaction.

c)Predict the concentration of the drug at 100 days when the initial concentration is 15.0 Î¼Units/mL

2.) 2.(20 points) The kinetics of the following reaction has been studied. A + B + C Ã P The initial rate of Aâs disappearance is given for mixtures of various initial concentrations (mM). [A] [B] [C] Initial Rate ( d[A]/dt) in mM sec-1)

1 1.5 1 2.26

2 1.5 1 4.51

1 3 2 4.48

2 3 1 9.05

a)Find the orders of reaction for A, B, and C. b)Find the reaction constant (k) and give its units.

c)Determine the concentration of P after 10 seconds when the initial concentration of A, B, and C are 10 mM. Assume a 1:1:1 stoichimoetry, and that there is no back reaction, P is the only product, and P does not react or decompose after being produced.

3.(20 Points) The oral administration of radioactive 131I is a standard treatment for thyroid carcinoma. One consideration for this therapy is assuring that other people do not receive significant radiation exposure. A recent study of 250 patients determined that the average half-life is 14 hours when orally administered to humans.

a)Determine the rate constant (k) for the removal of 131I.

b)According to federal regulations, individuals receiving 131I treatments must be confined as in-patients until their burdens of radioactivity fall to âsafeâ levels. Assume that a patient reaches a âsafeâ level when 95% of the 131I has been eliminated. Calculate the time needed for a patient to reach this level.

4. 30 points) The kinetics of the following reaction have been studied. I- + OCl-Ã OI- + Cl-The initial rate of I- disappearance is given for mixtures of various initial concentrations (mM). Condition [I-] [OCl-] [OH-] Initial Rate (- d[I-]/dt in mM sec-1)

1 2 1.5 1 0.18

2 4 1.5 1 0.36

3 2 3 1 0.36

4 4 3 2 0.72

A) Find the orders of reaction for I-, OCl-, and OH-.

B) Determine the reaction constant (k) and give its units.

C) Determine the half-life of I- when both OCl- and OH- are present at 50 Mm and I- is present at 0.1 mM.

Please answer but also explain all of them! Thank you!

CHEM-6 Midterm: Chem 6 Dartmouth Spring Exam 1S

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