The following information is to be used for the next two questions. Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are eco = 36400 and ENI = 5520 at 510 nm and eco = 1240 and e Ni = 17500 at 656 nm. A 0.322-g sample was dissolved and diluted to 150.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3- quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 1.129 at 510 nm and 0.305 at 656 nm in a 1.00-cm cell. Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample. 132 This problem is based on the additivity of absorbances. Set up an expression for the total absorbance at one wavelength due to both absorbing species; do the same for the other wavelength. You now have two simultaneous equations consisting of two unknowns. Because you are given a molar absorptivity, your concentration will be in molarity; you must convert to ppm. Because you are asked for the concentration of the initial solution, the size of your initial aliquot is not relevant, but if you dilute that initial aliquot during sample processing, a compensatory factor must be used in your computation. Submit Answer Incorrect. Tries 1/99 Previous Tries Calculate the concentration of nickel (in ppm) in the initial solution prepared by dissolving the sample. 132 Submit Answer Incorrect. Tries 1/99 Previous Tries
Catalysis and Enzymatic Reactions
Catalysis is the kind of chemical reaction in which the rate (speed) of a reaction is enhanced by the catalyst which is not consumed during the process of reaction and afterward it is removed when the catalyst is not used to make up the impurity in the product. The enzymatic reaction is the reaction that is catalyzed via enzymes.
Lock And Key Model
The lock-and-key model is used to describe the catalytic enzyme activity, based on the interaction between enzyme and substrate. This model considers the lock as an enzyme and the key as a substrate to explain this model. The concept of how a unique distinct key only can have the access to open a particular lock resembles how the specific substrate can only fit into the particular active site of the enzyme. This is significant in understanding the intermolecular interaction between proteins and plays a vital role in drug interaction.
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