| 39 Results |
| The Rate Equation (Other (1)) |
| A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook. |
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| The Rate of Reaction (Other (1)) |
| A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook. |
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| Iodine Clock Reaction (Movie/Animation, Audio/Visual (6)) |
| A solution of hydrogen peroxide and sulfuric acid is added to a solution containing iodide ion, thiosulfate ion, and starch. After some time the dark blue color of a triiodide-starch complex is observed. The influences of initial reactant concentrations on the reaction time are examined, as are the influence of volume and temperature. |
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| Rates of Reactions (Movie/Animation, Audio/Visual (6)) |
| The effects of a variety of variables, including concentration, temperature and catalysts, on reaction rate are shown. |
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| Halting the Briggs-Rauscher Oscillating Reaction (Movie/Animation, Audio/Visual (4)) |
| The Briggs-Rauscher reaction is demonstrated in three different ways. Catalase from a liver extract decomposes the hydrogen peroxide in an Briggs-Rauscher reaction, stopping the oscillations. |
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| Oscillating Reaction: Briggs-Rauscher (Movie/Animation, Audio/Visual (3)) |
| When a solution of malonic acid, starch, and manganese(II) ion is added to a solution of hydrogen peroxide, iodate ion, and sulfuric acid, gas bubbles form and the color of the resulting mixture oscillates periodically from colorless to amber to blue. |
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| Blue Bottle, Red and Blue Bottle (Movie/Animation, Audio/Visual (2)) |
| Color changes are caused by reactions of oxygen in the air with chemicals in a solution. The colors fade over time, but can be regenerated by shaking the flask containing the solution. |
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| Enthlapy-Thermodynamics (Movie/Animation, Audio/Visual (10)) |
| Reactions and demonstrations the explore thermodynamic concepts. |
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| Kinetics : RxnMechanisms (14 Variations) (Assessment Material (1)) |
Experiments show that the reaction of nitrogen dioxide and carbon monoxide
NO2 + CO  NO + CO2
has the following rate expression at high temperatures:
Rate=k[NO2][CO]
Is the following mechanism compatible with the experimental information?
(1) NO2 + CO O-N-O-C-O (slow)
(2) O-N-O-C-O NO + CO2 (fast)
Choose the best answer. |
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| Kinetics : RxnOrder (10 Variations) (Assessment Material (1)) |
For the reaction below, determine the order with respect to each reactant and the overall order.
2NO2(g) + F2(g) 2NO2F(g)
rate = k[NO2][F2] |
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| Kinetics : IntegratedRateLaw (6 Variations) (Assessment Material (1)) |
| The following kinetics information may be useful in answering this problem. 
Use the plots below to determine the order of the reaction with respect to A.
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| Kinetics : IntermediateInMech (15 Variations) (Assessment Material (1)) |
Suppose that for the reaction of nitrogen dioxide and carbon monoxide
NO2 + CO NO + CO2
the following mechanism has been proposed at high temperatures:
(1) NO2 + CO O-N-O-C-O (slow)
(2) O-N-O-C-O NO + CO2 (fast)
Check the box for each species that is an intermediate in this mechanism. |
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| Kinetics : RateConstantUnits (8 Variations) (Assessment Material (1)) |
| The isomerization of CH3NC to CH3CN has a rate constant of 0.46 s-1 at 600 K.
(1) Based on the units of the rate constant, what is the order of the reaction? {1:MULTICHOICE:zero-order#No, that is not correct.~=first-order#Correct!~second-order#No, that is not correct.~third-order#No, that is not correct.}
(2) What is the concentration of CH3CN after 0.20 minutes of reaction if the initial concentration is 0.10 M? {1:NUMERICAL:=4e-4:1e-5#Correct!~%50%4e-4:5e-5#Close, but not quite.}(Do not include units!)
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| Kinetics : CatalyticConverters (4 Variations) (Assessment Material (1)) |
The following table illustrates the changes in emissions requirements for automobiles: | Pollutant | 1970 Emissions | 1990 Emissions | CA ultra-low emissions |
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| CxHy | 1.5 g/mile | 0.25 g/mile | 0.04 g/mile | | CO | 15 g/mile | 3.4 g/mile | 1.7 g/mile | | NOx | 3.1 g/mile | 0.4 g/mile | 0.2 g/mile |
Catalytic converters are used in automobiles to convert pollutants in engine emissions to benign products. Catalytic converters in today's automobiles are made of a porous ceramic brick that has been coated with catalysts, additives, stabilizers, and support materials. Corning has developed bricks that have very thin-walled channels with 600 channels per square inch. Which of the following research goals did they target? |
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| Kinetics : ArrheniusTemp (3 Variations) (Assessment Material (1)) |
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The activation energy for the isomerization of cyclopropane to propene is 274 kJ/mol. By what factor does the rate of reaction increase as the temperature rises from 500oC to 550oC assuming all else remains constant? (R = 8.314 J/mol k)
Hint: This is asking for the ratio of rates which is proportional to the ratio of the rate constants, all else being equal. |
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| Kinetics : ArrheniusActEnergy (4 Variations) (Assessment Material (1)) |
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The rate constant for the first-order dehydration of tert-butyl alcohol at 500oC is 1.20 x 10 -4 s -1. The rate constant for this process at 600oC is 6.80 x 10 -3 s -1. Calculate the activation energy for this reaction in kJ/mol. (R = 8.314 J/mol K) |
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| Kinetics : Enzyme (7 Variations) (Assessment Material (1)) |
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Trypsin assists in digestion by breaking proteins down into smaller peptides. However, this process is not as efficient in the presence of fluorophosphates. Identify the role of each of these components. |
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| Kinetics : CompareEnergyProfile (11 Variations) (Assessment Material (1)) |
Consider the following reactions that take place at the same temperature, begin with the same molar concentrations, and whose energy profiles are presented below:
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| Kinetics : ConcVsTimeGraph (8 Variations) (Assessment Material (1)) |
The following graph shows the change in concentration as a function of time for the reaction:
2NO2(g) + F2(g) 2NO2F(g)
What do each of the curves A, B, and C represent?
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| ChemPaths 104 M Feb 21 () |
| Today in Chem 104:
* Lecture: Rate Laws
* Reading:
Kotz:, Ch. 15, Sec. 3-4
Moore, Ch. 13, Sec. 3-5
* Homework #5 due by 11:55 pm F Feb 25
* Excel assignment due in first discussion section this week
* Quiz 4 in second discussoin section
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| ChemPaths 104 F Feb 18 () |
| Today in Chem 104:
* Lecture: Rates of Reaction
* Reading:
Kotz: Ch. 15, Sec. 1-2
Moore, Ch 13, Sec. 1-2
* Homework #5 due by 11:55 pm F Feb 26
* Excel Assignment due at first discussion section
next week (week of Feb. 21)
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B, which of the following statements about the rates of forward and reverse reactions is true at time x? 
