Chapter 41, Problem 1ASA

Water sample A has a turbidity reading of 555 NTU. If a 50 ppm standard has a turbidity reading of 50 NTU, what is the concentration of the analyte in A that causes the water to be turbid?

A water sample B has a turbidity reading of 50 NTU. If a 50-ppm standard has a turbidity reading of 100 NTU, what is the concentration of the analyte in A that causes the water to be turbid? a. 50 ppm b.100 ppm c. 75 ppm d. 150 ppm e. 25 ppm

If an analytical method relies on a measurable property of an analyte that can be correlated with the amount of the said analyte, what type of analytical method is it?   Oxidative methods   Instrumental methods   Blank Correction methods   Classical methods

Amy is testing the concentration of muriatic acid (hydrochloric acid) to check that the concentration is within certain limits. She titrated a 15.0 mL sample (diluted by a factor of 10) with a standard sodium hydroxide solution. A volume of 10.00 mL of 0.125 mol/L sodium hydroxide is used to neutralize the acid. a. Calculate the concentration of HCI? Show your work. b. Write down any three steps of the procedure (Past tense, passive form) followed.

The value of 4-chlorobutanic acid is 3.02 x 10^-5.

Aliquots of a 0.5 mg/mL standard of BSA were used to construct a standard curve for the Bradford protein assay. The tubes contained the following amounts of the BSA solution: 0, 20, 40, 60, 80, 100 μL. Each sample then had water added to make the final volume 100 μL. The corresponding absorbencies after adding Bradford reagent were the following: 0, 0.05, 0.09, 0.14, 0.19, and 0.22. If you took 20 μL of an unknown and added 80 μL of water, mixed, took 10 μL of the mixture and 90 μL of water and added the Bradford reagent and saw an absorbance of 0.08, what was the protein concentration of the undiluted unknown to one decimal place?

6 I-  +  BrO3-  +  6 H+ ----- 3 I2  +  Br-  +  3 H2O Rate= k[I-]m[BrO3-]n[H+]p rate= (∆[I2])/(3*∆time)             [I-]   0.010M [S2O3-2] 0.0010M H2O   [BrO3-] 0.04M HCl  0.10M Starch Indicator (sec.)   Volume, ml Volume, ml Volume, ml   Volume, ml Volume, ml     1 10 10 20   10 10 1-3 drops 301.90 2 20 10 10   10 10 1-3 drops 213.28 3 10 10 10   20 10 1-3 drops 214.92 4 10 10 10   10 20 1-3 drops 86.45 Temperature of Reaction: _______20 C________ 1. Using the dilution equation (M1V1 = M2V2) calculate the concentration of the I-, BrO3- and the H+ (HCl) in the final mixture just prior to any reaction. 2. Calculate the rate for each experiment as explained in the background information. 3. Using the information above determine the rate law (m, n and p) for the reaction. Show all calculations/reasoning in your notebook. m_____________ n_________________ p…

Professor Forni has hired you as a research assistant and you need to make an X-gal staining solution for your sections containing 5mM potassium ferrocyanide, 5 mM potassium ferricyanide, 2 mM MgCl2, 0.1% Tween and 0.1% BCIP. You need 50 ml. As you are getting ready you discover that your colleague has used up all but 20 mg of the MgCl2.How much MgCl2 do you need to make 50 ml of X-gal staining solution? Do you have enough? Hint: we only care about MagnesiumChloride here. (MW MgCl2 is 95.21 g/mol)

Table 1. Crystal violet Concentration Test tube   10.0 x 10-6MCV(mL)  DistilledH2O (mL)  Concentration (M) 1                      0                               15.00                    0.00 2                    3.00                              12.00 3                    6.00                               9.00 4                    9.00                                6.00     5                    12.00                               3.00 6                     15.00                                0    1.Calculate the Concentration of the Crystal Violet Solutions in Table 1 of the Procedure using V initialx M initial = V diluted x M diluted (Note: V diluted = 15 mL). Record the concentrations in Table 1 AND in the Data table in the report sheet.