Since alkenes are immiscible with concentrated HBr, tetrabutylammonium bromide is used as a phase-transfer catalyst. It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
With reference to figure 1, the peak performance of catalase was at 30℃, which was the closest to its usual environment of body temperature at 37℃ (Buddies, 2012). Figure 1 depicts that at 0℃ the reaction rate was 3, whereas at 100℃ the reaction rate was 0, meaning that the catalase was denatured. Additionally, figure 1 demonstrates that reaction rate increases as temperature increases until catalase reaches its optimum temperature of 30℃, in which case the reaction rate decreases. Once again, the general trend displayed by this experiment is that reaction rate will increase until an enzyme reaches its optimal temperature, then the reaction rate will
ABSTRACT To catalyze a reaction, an enzyme will grab on (bind) to one or more reactant molecules. In this experiment we examined how increasing the volume of the extract added to the reaction would affect the rate of the reaction. The enzyme used was horseradish peroxidase which helps catalyze hydrogen peroxide. Using different pH levels, the absorbance rate of the reaction was measured to see at which condition the enzyme worked best. The rates of absorption were calculated using a spectrophotometer in 20 second intervals up to 120 seconds.
The residual HA concentration of the settled water could be controlled within 1.50 mg/L. Meanwhile, the zeta potential of the coagulated HA generally increased with increasing CB dosage, indicating that the negative charges on the HA molecules was neutralized by the positive charges on the CB surface. This results are consistent with existing literature data for inorganic coagulants [4,25]. The number of charges on both HA and CB surfaces varied with pH , which might affect HA removal by coagulation. It was determined that as the solution pH decreased
By observing figure 3, the more enzyme that is available, the faster the reaction rate is. The optimal enzyme concentration was chosen based on the R2 values from figure 2. The highest observable rate also had the best R2 number, which was closest to one. This enzyme concentration was used in part 2. In part 2, using the Michaelis-Menten kinetics of the enzyme, identified the inhibitor (75 mM phenylalanine) as an uncompetitive inhibitor.
The experimental Ksp at 291.15 K was found to be 7.10 x 10-4 + 5 x 10-6 and compared to the literature value of 3.8 x 10-4. Since ΔH° reaction and ΔS° reaction was assumed to be nearly independent of temperature, the change in enthalpy and entropy of the reaction was found using the gradient and intercept respectively of the linear plot of lnKsp versus the reciprocal of temperature. Using van’t Hoff equation, ΔH° reaction and ΔS° reaction was found to be 44 ± 1.3 kJ K-1 mol-1 and 89 ± 4 J K-1 mol-1
We measured how long it took for the high pH test tube to change color versus how long our control took. The Lugol’s Iodine test identifies for complex carbs. In our case, if the substance changed to a light brown color, the test was negative and the substance contained like glucose, and if the substance changed to a dark brown or black color, then the test was positive and the substance contained complex carbohydrates like starch. The substance with the high pH changed to a light brown at a time of 12 minutes and 49 seconds and the control changed to the same color at an earlier time of 11 minutes and 15
The obtained binding constant was used for the calculation of the standard free energy changes of the reaction (ΔG°) by applying the following equation: ΔG° = −2.303 RT log K where ΔG° is the free energy change of the reaction (kJ mol−1), R is the gas constant (8.314 J K-1 mol-1), T is the absolute temperature in Kelvin and K is the binding constant of the drug–metal complex. The estimated value of ∆G was –29.8 KJ mol-1. The highly negative value of the Gibbs free energy indicates the high spontaneity of the complex formation reaction at room
That means the non-polar molecules will spend a shorter time in solution in the mobile phase and it will slow them down on the way through the column. So over all polar molecules will travel faster through the column than non-polar molecules. The speed of the molecules going through the column is very important. Because the time it takes them to go through the column and reach the detector is the determining factor in the analysis of the compound. That time is called retention time.
4.8 Entropy generation Another way of assessing the performance of enhancement techniques is the consideration of the entropy generation rates as a result of applying the enhancement technique [34,46,48]. With this, the aim is to minimise the irreversibilities and the technique with the lowest entropy generation rates is desirable. Further, enhancement techniques with the entropy generation ratio, Ns,en less than 1 makes thermodynamic sense. In this section, results of entropy generation analysis for a parabolic trough receiver with twisted tape inserts are presented. 4.8.1 Heat transfer and fluid flow irreversibilities Heat transfer and fluid flow irreversibilities are the two irreversibilities present in convection heat transfer problems.