Le Chatelier's principle states that a chemical system must have a shift in direction in order to force the system to reach equilibrium.

a.true

b.false

Calculate the mass of ammonium chloride required to prepare 25 mL of a 2.0 M solution, and the mass of calcium chloride required to prepare 25 mL of a 2.0 M solution.

A 100 mg vitamin C tablet weighed 1.627 g. A student crushed the tablet and transferred 0.159 g of the crushed powder into a 100 mL volumetric flask, dissolved the powder in ~30 mL DI water, then filled the flask to the calibration line with DI water and mixed well to create Solution 1. The student then transferred 23.2 mL of Solution 1 into a 100 mL volumetric flask and diluted to the calibration line with DI water to create Solution 2. Calculate the expected concentration (in mM) of ascorbic acid in Solution 2.

The three reactions below are all at equilibrium simultaneously in solution.
Ca2+ (aq) + C2O42- (aq) « CaC2O4 (s)

H2C2O4(aq)«H+(aq)+HC2O4-(aq)

HC2O4- (aq) « H + (aq) + C2O42- (aq)
a. If HNO3 is added to this solution, would you expect to see more or less of the precipitate (CaC2O4) formed in the solution? Explain your reasoning by showing the effect of the addition of HNO3 on the equilibrium for the reaction.

1. Calculate the volume in milliliters (mL) of a 6.00 M NaOH solution needed to make 5.00 x 102 mL of a 0.100 M NaOH solution. (Recall that M = molar = mol/L, and show all your work).

2. An approximately 0.1 M NaOH solution was standardized with KHP by titration to a phenolphthalein endpoint. From the following data, calculate the average molarity of the NaOH. The molar mass of KHP is 204.22 g/mol.

Trial 1 Trial 2 Mass of weighing paper + KHP 2.1467 g 2.1719 g Mass of weighing paper 1.4125 g 1.4136 g Mass of KHP __________ __________ Moles of KHP __________ __________ Final buret reading 31.80 mL 32.67 mL Initial buret reading` 0.15 mL 0.04 mL Volume of NaOH (mL) __________ __________ Molarity of NaOH (moles per liter) __________ __________ Average molarity __________

3. Calculate the average molarity, standard deviation (SD), and percent (%) variation of the three titration molarities given below. Recall: % variation = (SD/mean)*(100%).

Molarity of HCl: 0.3087 M 0.3083 M 0.3092 M

Average Molarity: ___________________ ± _____________ (SD) [UNITS!]

Percent (%) variation: ____________________ %

Is the percent variation less than 1%? _________

Why does the nitration of bromobenzene form ortho and para products in an Electrophilic Aromatic Substitution reaction?

Find an example of a detergent. Using a line drawing, draw the detergent and provide its name.

Discussion about; Losing and gaining weight

Obesity is a big problem in the industrialized countries. Nutrition facts now have been added to the labels on the food items, so people can use them to regulate their diet. Do you think that including the nutrition facts in the food labels is going to solve the obesity problem? What other suggestions do you have to solve this problem?

Please make sure to type it and make it clear.

A buffer solution contains 0.33 mol of hypoiodous acid (HIO) and 0.75 mol of sodium hypoiodite (NaIO) in 4.50 L.
The K_a of hypoiodous acid (HIO) is K_a = 2.3e-11.



(a) What is the pH of this buffer?

pH =  


(b) What is the pH of the buffer after the addition of 0.26 mol of NaOH? (assume no volume change)

pH =  


(c) What is the pH of the original buffer after the addition of 0.08 mol of HI? (assume no volume change)

pH =  

Calculate the percent ionization of arsenous acid (H₃AsO₃) in solutions of each of the following concentrations (K_a = 5.1e-10.)

(a) 0.206 M

%



(b) 0.556 M

%



(c) 0.822 M

%

Consider a the titration of 0.685 L of 0.773 M ascorbic acid (H₂C₆H₆O₆) with 1.76 M NaOH. What is the pH at the second equivalence point of the titration?

Determine the pH of each of the following solutions.

(a) 0.637 M hydrosulfuric acid (weak acid with K_a = 9.5e-08).





(b) 0.764 M hypoiodous acid (weak acid with K_a = 2.3e-11).





(c) 0.458 M pyridine (weak base with K_b = 1.7e-09).

Consider the following reaction. It is occuring in a closed system and it is currently at equilibrium:

Label each of the following statements with is effect on the reaction
(shift towards products, shift towards reactants or no change) 1. Removing hydrogen gas.
(shift towards products, shift towards reactants or no change) 2. Decrease the pressure on the reaction vessel
(shift towards products, shift towards reactants or no change) 3. Placing the reaction vessel in an ice bath
(shift towards products, shift towards reactants or no change) 4. Increase the size of the vessel.
(shift towards products, shift towards reactants or no change) 5. Removing water vapor from the vessel.

FIVE CLINICAL CHEMISTRY QUESTIONS:

1. What is the origin of AFP in the amniotic fluid? When do AFP levels peak in amniotic fluid? In maternal circulation? When should maternal blood levels be drawn?

2. What other test performed on amniotic fluid may confirm the diagnosis of a NTD? What values (elevated, decreased) will this assay take if a NTD is present?

3. Describe the delta O.D. spectrophotometric test for amniotic fluid bilirubin and discuss the clinical significance of abnormal results. (Include a description of Hemolytic Disease of the Newborn)

4. Briefly describe the changes in lipid composition of amniotic fluid before and during fetal lung maturation.

5. Describe the triple marker screen for Down syndrome and the expected changes from normal values for each in an affected pregnancy.