Is ibuprofen sold as a single enantiomer or a racemic mixture? How many stereocenter(s) does the molecule have? Does ibuprofen exist in diastereoisomeric form?

Explain why chirality in molecules is an important property for ibuprofen

The following data were collected for a phosphorescent paint being proposed for use in coating highways.

Calculate the half-life for the paint.

What is the intensity of the light at the 2nd half-life?

What is the intensity of the light at the 3rd half-life?

Explain how coulometry differs from amperometry. Why does coulometry give better precision, while amperometry is more suitable for sensors?

Select the pair of substances in which an acid is listed followed by its conjugate base. A) H+, HCl

B) NH3, NH4+

C) HPO42-, H2PO4-

D) HCO3-, CO32-

E) CH3COOH, CH3COOH2+

The enthalpy of vaporization of Substance X is 8.00kJmol and its normal boiling point is −100.°C . Calculate the vapor pressure of X at −117.°C .

round to 2 sig figs

A 35.00mL sample of aqueous lactic acid(HC3H5CO3) is titrated to the equivalence point with 65.00mL of 0.15 M KOH(aq). What is the pH of the resulting solution? The Ka for lactic acid is 8.3x10^-4. The correct answer is 8.03 but I am unsure about the steps in getting there.

2. Using the same method, answer the same questions for mixing 30 g of hydrogen fluoride and 30 g of glass (which is made of silicon dioxide) with focus on determining the percent yield of silicon tetrafluoride (and water). Silicon tetrafluoride is found in volcanic plumes and has some limited use in microelectronics.

HF(g) + SiO2(s) → SiF4(g) + H2O(l)

a) Write a balanced chemical equation for the equation above.
b) From your balanced chemical equation, what is the molar ratio between the reactants and products?
c) What is the stoichiometric amount of moles of SiF4 that can be formed when 30 grams of HF and 30 grams of SiO2 are reacted?
d) What is the theoretical amount (in grams) of nitric acid that can be formed when 30 grams of HF and 30 grams of SiO2 are reacted?
e) What is the percent yield of Silicon tetrafluoride?
f) How much of the excess reagent remains?

Which of the following are true statements about ketones?

Select all that apply:

• Acetone can be used as a solvent for lacquer (including fingernail polish).

• They each contain a functional group in the middle of a carbon chain with the structure −CO.

• They are named using the suffix -al.

• They are named using the suffix -one.

1. What is the name of the intermolecular force caused by an instantaneous dipole in each below particles?

a)ionic attraction b)dispersion forces c)covalent bond d)hydrogen bond

2. For each of the following compounds, indicate which intermolecular force is the most important.

a)FCN b)HCN c)C₂H₆ d)CH₃OH

Fischer Esterification

Acetic Acid + Ethanol in the presence of Dowex, a solid catalyst. 4 samples were placed in 4 tubes, heated in a water bath.

Test tube 4 was left in the water bath overnight. When testing sample #4 with GC and NMR, one product was expected - the ester, ethyl acetate. However a small portion of acetic acid was present. I understand acetic acid is often used in excess (La Chat) but the ethanol was in equal ratio to the acetic acid, so should it not have appeared as well? I know its an equilibrium, but if one is present, wouldn't both acetic acid and ethanol be there if it had gone in reverse?

Why is it that temperature fluctuations during atomization (i.e. in the plasma or flame) are a big problem for atomic emission spectroscopy, but less of a problem for atomic absorbance spectroscopy? Include an equation in your answer.

In an experiment reported in the scientific literature, male cockroaches were made to run at different speeds on a miniature treadmill while their oxygen consumption was measured. In one hour the average cockroach running at 0.08km/hr consumed 0.8 mL of O2 at 1 atm pressure and 24 ?C per gram of insect weight.

a)

How many moles of O2 would be consumed in 1 hr by a 5.4?g cockroach moving at this speed?

b)

This same cockroach is caught by a child and placed in a 1-qt fruit jar with a tight lid. Assuming the same level of continuous activity as in the research, will the cockroach consume more than 20% of the available O2 in a 48-hr period? (Air is 21 mol percent O2)

A.

A mixture of carbon dioxide and argon gases, in a 7.78 L flask at 41 °C, contains 12.9 grams of carbon dioxide and 11.9 grams of argon. The partial pressure of argon in the flask is__atm and the total pressure in the flask is __atm.

B.
A mixture of carbon dioxide and helium gases is maintained in a 5.92 L flask at a pressure of 2.30 atm and a temperature of 88 °C. If the gas mixture contains 14.1 grams of carbon dioxide, the number of grams of helium in the mixture is __g.