Which error will lead to negative deviation from the theoretical Keq? a. cuvette was filled to the brim with the sample. b. cuvette was washed with sodium hydroxide instead of distilled water. C. standard with the highest concentration was used in autozero. d. cuvette was misplaced such that the HO side faces tbe light

3. Compare column, thin-layer, and gas chromatography in terms of: a. mobile phase b. stationary phase.

value of Ksp I got was 1X10*-5. It was achieved by titration of 20 ml Ca(OH)2 against 0.05 M HCl. Average of 11.9 ml HCl was used....

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QUESTION 15 To improve the accuracy of our linear fit between absorbance and concentration, a. add an extra data point to your linear regression where you make the assumption that pure water has an absorbance of zero. b. make sure that you choose a "Linear Regression" curve fit. c. ensure that there are no air bubbles in the cuvette. O d. use the data points only at the lower end of the concentration range because Beer's Law is not applicable for higher concentrations. QUESTION 16 What laboratory equipment do you need to prepare a 0.250 M stock solution of NaCI? O a. buret, graduated cylinder, analytical balance b. beaker, volumetric flask O. volumetric pipet, analytical balance d. analytical balance, volumetric flask

35. The stationary phase, as well as mobile phase, are liquid in Adsorption column chromatography O Partition column chromatography Gel column chromatography

Match Column A with Column B. v Distance traveled by the solvent A. Silica gel G Adsorbent used in TLC B. Eluent v High affinity to stationary phase C. High Rf value v High affinity to mobile phase D. Point of origin v Liquid that comes out of the column E. Low Rf value F. Solvent front G. Silica gel H. Eluate

2. In performing an unknown analysis, a student did a sloppy separation of PbSO4 from the filtrate. Some PbSO4 was mixed with the filtrate. What effect may this mistake have on the determination of the following ions? (Answer NO EFFECT or FALSE POSITIVE (indicating the student would think this ion is present when, in fact, it is not)). a.) Pb+2 c.) Zn+2 b.) Ag d.) Fet3

24. What important analytical method is employed that include analysis of standard reference materials when available, analysis by a different analytical method, analysis of "spiked" samples, and analysis of synthetic samples approximating the chemical composition of the test samples? A. Checking for Analytical Sensitivity B. Determining the Validity C. Construction of Calibration curve D. Identification of the Detection limit 25. It is considered to be the least effective control measure when it comes to minimizing danger in laboratory experimentation practice. A. Elimination B. Substitution C. Administrative controls D. Personal protective equipment

Chemistry A chromatographic peak has a retention time of 120 s. the width at the base of the peak equals 3.2s, at the intersection of the sides of the peak with the baseline. If the column is 200 cm long. a.What is the number of theoretical plates. b. The equivalent height of each plate. c. The sensitivity of the method if the retention time of the mobile phase is 50 s.