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CHEM 142 Lecture Notes - Lecture 12: Chch-Dt, Horse Length, Intensive And Extensive Properties

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coralplatypus226

7 Jul 2016

School

Emory University

Department

Course

Professor

Mulford Douglas

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Split your table into two groups for this exercise half of you will be the reactants and you will start off with 100 pennies. The other half of you will be the products and you will start off with 0 pennies. If you are to set to the side a fraction of a penny, do so only if the fraction is greater than half a penny. (the total number of pennies cannot deviate from 100. ) Record in the table how many pennies the. Reactants and the products have after each passage of time. time. 0: when the numbers of pennies held by each group in the exercise no longer changed, we say that the system has reached equilibrium. Explain your answer using specific numerical data from the coin simulation. Reactants passed to the products, and the rate of the reverse reaction (kr) is equal to the fraction of pennies the products passed to the reactants.

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Related Questions

ENT ives To determine equilibrium concentrations for species in solution . Examine temperature effects on reaction equilibrium Investigate the shift in equilibrium from different stresses on a system kills . Use colorimeter to determine unknown solution concentrations ced .Preparing temperature baths to change reaction conditions tionEquilibrium is defined as a state in which the concentrations of both the reactants and products have no tendency to change with time. We can restate this by saying that the rate of the forward reaction is equal to the rate of the reverse reaction. Recall that with rate we are simply defining how fast a reaction is proceeding, a speed at which the reaction proceeds. Take note that when writing an equilibrium expression, pure liquids (denoted by l or 2) and pure solids (denoted by s) are omitted. Typically we express the equilibrium by K or Kp where c and p denote either concentration or partial pressure respectively. We refer to this value of K, or Kp as an equilibrium constant For any reaction, Kc can be written as the product of the concentration of products, raised to their stoichiometric coefficients, divided by the product of the concentration of the reactants raised to their stoichiometric coefficients. See Equation (5-1) below for an example: aA(aq) + bB(aq-cC(aq) + dD(aq) (5-1) A] [B]b As mentioned before, K, or K, are equilibrium constants meaning that they will have the same value unless temperature is changed. This brings in two important ideas 1) We can perturb the equilibrium concentrations of a reaction, say [A] for instance which will cause the other concentrations to shift so that K for the reaction remains constant. 2) If we change temperature, we will either increase or decrease our value of K depending on the specific reaction we are examining. Determining K, and Equilibrium Concentrations During lecture we often discuss the idea of using ICE tables as a method for organizing and calculating concentrations of reactions as they proceed towards equilibrium. In a typical ICE table you need to know initial concentrations and the magnitude of K to determine the equilibrium concentrations. Alternatively, if you know the equilibrium concentrations for a reaction you can calculate K. For this experiment we will be examining a complex ion formation, when iron(III) ion

Can anyone tell me how to get the percent and theoretical yield here?

- 2129 11 W- CH 4521-6: Fischer Esterification Introduction Esters are among the most widespread of all naturaly liquids that are responsible for the pleasant odors of fruits and flowers. Examples are ethyl cinnamate, whic occurring.compounds. Many simple esters are fragrant Ts the smell of cinnamon, and isobutyl acetate, contributing to the aroma of cherries, raspberries and of giycerol and fatty acids Esters are characterized by having the functional group:RO.R,where Escher esterification. This reaction refluxes a carboxylic acid inan . However, the most common esters found in nature are fats and ble oils, which are esters a carbon is double-bonded to one alcohol, creating the ester plus water as oxygen atom and sin The most classic method for creating an ester is the products: estor orer alcohai +R-OH catalyst A strong acid, traditionally sulfurits acid, is used as a catalst. Since the reaction is at equilbrium, simply reacting one mole of asid with one mole of alcohol will give a mixnture of starting materals and yield of the product may be improved using le Chatelier's principle: . Using the alcohol as a solvent (le. arge excess wil hlp push the equllbrium to the right By sequestering water (a reaction product), the equilibrium is pushed to the right. The use of a solvent which forms low-bolling azeatropes with water, such as toluene, in conjunction with a Dean-Stark apparatus has a similar effect, as is the use of other drying agents like molecular sieves Since low molecular weight esters typically have lower boling points than their parent carboxylic acids and alcohols because they are not able to form hydrogen bonds, the ester products may be distilled out of the reaction vessel as they are formed. By removing the ester product in a reactive distillation, the equilibrium once again lies to the righ For today's experiment, you will be able to choose which sweet-smelling ester you want to make. The table of reactants below gives you an idea of the range of smells. An ester will esterification reaction. This reaction involves mixing an alcohol with a carboxylic acid to form an ester and water. The reaction is reversible and an example is shown below be synthesized using the Fischer catalyst acetc acid propanopropyl acetate (pear) 47

I already did the counting part.
First shake to the last shake were:
68
38
32
25
17
8
6

3

2

1

Count out 200 M&Ms and place them with the "M" side up on the tray. The tray represents a rock sample and the candies with the marked side represent the entire radioactivity the sample contains initially. Give the tray a shake so that many of the candies flip over. One shake represents the passage of 5,000 years. Count and remove all of the M&Â®s that flipped over to the unmarked side. These represent the radioactivity that underwent nuclear decay and transmutated into a different element. Repeat Steps 2 and 3 until all the candies are gone. (If you give the tray a shake and none of the candies flip over, be sure to record the shake as the passage of 5,000 years but with zero transmutations.) Normally, eating in the lab is not permissible; make sure that everything is clean and properly disposed of Plot a line graph with the number of "radioactive" particles left (you must start with 200 at time = 0. Subtract the first amount that flipped over for the first 5,000 years. Then subtract the second amount from that number -- not the 200 -- at 10,000 years, etc.) versus time (on the horizontal axis). Be sure that it is properly labeled and titled. Explain why your "radioactive decay" curve is not perfectly smooth; in other words, besides the fact that this is not really radioactive and you are shaking a tray instead of the passage of real time, why are real radioactive decay curves very predictable? What do mathematicians call the shape of this curve? If the half-life of your sample is 5,000 years, calculate the value for k, the rate constant. Be sure to show your calculations. Assume that your "radioactivity" was C-14 (carbon-14, carbon with mass number 14) and that it undergoes beta decay. Write the balanced nuclear equation for this reaction. Carbon dating can be used to get a measurement of the age of a carbon-containing sample. (Scientists actually use mass spectroscopy and measure ratios of isotopes, which is a bit more complicated than can be replicated here.) Using the curve you created in Step 1, determine the age of a sample with this amount of radioactivity left: 75% 50% 25% 0%