The spherical volume of a H2O molecule is 0.00818 nm3 (in reality, this is a very close approximation of the volume of a H2O molecule). How long a "chain" would a 0.65 of a mole of water molecules be?

Calculate the isoelectric point of the following amino acid – You must show your work! pKa of the following groups α-COOH has 2.09 α-NH3 has 9.82 R group has 3.86 Aspartate

Briefly explain the principle of SDS-polyacrylamide gel electrophoresis. What is the purpose of the SDS? Which proteins midrate slowest by SDS-PAGE?

Part A: How acidic would the external pH need to become in order to make it possible to synthesize one ATP molecule from the energy delivered when one proton enters the mitochondrial matrix? (Assume ATP formation requires 52.0 kJ/mol, 37 degrees celsius, membrane potential -0.12V, and matrix pH 7.2)

Part B: Comment on whether this pH is feasible, BE SPECIFIC!

Consider the structural changes that occur in the following molecules. BH3, CH4, NH3, H2O, HF

a. according to Lewis and VSEPR theory, why doe these changed occur?

b. what are the ideal bond angles for each structure, and which are expected to be distorted?

A 2.500×10⁻² M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.3 mL . The density of water at 20.0∘C is 0.9982 g/mL.

Calculate the molality of the salt solution. X_NaCl = 2.506 X 10^-2 m

Calculate the mole fraction of salt in this solution. X_NaCl = ???

Calculate the concentration of the salt solution in percent by mass. Percent by mass NaCl = ???

Calculate the concentration of the salt solution in parts per million. Parts per million NaCl = ???

6. During the synthesis of a Grignard reagent in diethyl ether solvent, bubbles are observed on the surface of the magnesium. Select the correct identity of the bubbles.

a. The bubbles are gaseous O2.

b. The bubbles are gaseous H2.

c. The bubbles are gaseous diethyl ether.

d. The bubbles are gaseous magnesium byproducts.

7. Prior to the synthesis of a Grignard reagent, the magnesium that is used in the reaction must be activated. Select the action that best describes this activation step.

a. exposing the magnesium to UV light to promote its electrons to an excited state

b. increasing the temperature to 150 °C to oxidize the surface layer of magnesium

c. soaking the magnesium in water to clean the surface layer

d. scraping or crushing the magnesium to expose fresh, unoxidized surface

8. A synthesis procedure calls for the trituration of the crude product prior to recrystallization. Select the most likely consequence of failing to triturate the crude reaction product.

a. Less of the crude product will recrystallize from the recrystallization solvent.

b. Less of the crude product will dissolve into the recrystallization solvent.

c. The recrystallized product will contain less impurities than it would if it had not been triturated.

d. The mass of the recrystallized product will be lower than it would have been if it were triturated.

9. Select the term that describes the act of grinding a solid with a stirring rod or spatula in the presence of a solvent.

a. salting out

b. centrifugation

c. sonication

d. trituration

10. Select the action that will NOT help increase the yield of a Grignard reagent.

a. dry the glassware in an oven prior to use

b. use only anhydrous ether as solvents

c. scrape or grind the Mg pieces prior to use

d. rinse the reaction glassware with acetone immediatelt prior to use

11. A reaction product mixture containing hydrocarbons in diethyl ether is washed with saturated aqueous sodium chloride (brine) solution in a separatory funnel. Select the most likely reason for this step.

a. This step is to extract sodium chloride into the ether layer.

b. This step is to remove water from the ether layer.

c. This step is to extract the ether into the aqueous layer.

d. This step is to extract the hydrocarbons into the aqueous layer.

1. The glassware that is to be used for a Grignard reaction is washed with water and acetone, and dried thoroughly before the reaction is to be performed. Select the most likely reason why.

   a. Acetone is needed to react with the silanol groups on the surface of the glassware.

   b. The acetone adheres to the sides of the glassware as it dries, and it catalyzes the formation of the Grignard reagent.

c. Grignard reactions are highly endothermic, and residual water will freeze during the reaction.

d. If the glassware is not completely dry, residual water or acetone will react with the Grignard reagent.

2. A Grignard reaction is to be performed in diethyl ether solvent. Select the appropriate grade of diethyl ether for a Grignard reaction.

a. anhydrous grade

b. spectroscopy grade

c. ACS grade

d. technial grade

3. Crude triphenylmethanol was recrystallized using a 2:1 mixture of hexane:ethanol. Select the most likely reason why this recrystallization solution was chosen over pure ethanol.

a. Formation of triphenylmethanol crystals in the presence of pure ethanol is rapid, resulting in lower purity.

b. Triphenylmethanol is very soluble in pure ethanol and its recovery during recrystallization would be low.

c. Hexane stabilizes the phenyl groups of triphenylmethanol, protecting it from decomposition in the presence of heat.

d. Triphenylmethanol is relatively insoluble in pure ethanol, and not enough of it would dissolve for a recrystallization.

4. Which of the following is NOT a reason why heating a reaction mixture directly on the surface of a hot plate can be problematic?

a. Hot plates can heat glassware unevenly, which can lead to stress and cracking.

b. It is difficult to measure and maintain the temperature of a reaction when using the common, traditional style of hot plate.

c. Flammable solvents with low boiling points may ignite.

d. Hot plates cannot heat above 200 °C.

5. A Grignard reaction is performed by heating phenylmagnesium bromide and benzophenone under reflux in diethyl ether. Given that diethyl ether boils at 35 °C and benzophenone boils at 305 °C, select the appropriate temperature for the reflux.

a. 35 C

b. 25 C

c. 305 C

d. 100 C

1.How much heat (in kJ) is required to warm 13.0 g of ice, initially at -10.0 ∘C, to steam at 109.0 ∘C? The heat capacity of ice is 2.09 J/g⋅∘C and that of steam is 2.01 J/g⋅∘C.

2. How much energy is released when 42.5 g of water freezes?

3. Suppose that 0.86 g of water condenses on a 75.0 g block of iron that is initially at 24 ∘C.

If the heat released during condensation goes only to warming the iron block, what is the final temperature (in ∘C) of the iron block? (Assume a constant enthalpy of vaporization for water of 44.0 kJ/mol.)

Express your answer using two significant figures.

Although knowing exactly how much Aspirin is in a tablet is good indicator of
how much dose was given to a person, it does not however, give the exact
quantity absorbed into the bloodstream. Describe what experiment you would
perform to try and decipher the quantity of Aspirin absorbed.

Given the spectral data, determine the structure of the following compound. Show all work. Combustion analysis: C: 85.7% H: 6.67% MS: Molecular ion at m/z= 210, base peak at m/z=167 1H-NMR: 7.5-7.0 ppm (m, 10H) 5.10 ppm (s, 1H) 2.22 ppm (s, 3H) 13C-NMR: 206.2 (C) 128.7 (CH) 30.0 (CH3) 138.4 (C) 127.2 (CH) 129.0 (CH) 65.0 (CH) IR: Strong absorbance near 1720 cm -1

1. An aqueous solution of calcium chloride, CaCl2, is 3.464 M and has a density of 1.2816 g cm-3. Assuming you have 1 liter of this solution answer the following questions.

a) Use the density to calculate the mass of the solution 1281.6 grams of solution

b) Given that you have 1 liter of solution how many moles of CaCl2 are in the solution? mol CaCl2

c) Calculate the mass of CaCl2 in the solution grams CaCl2

d) Determine the mass of water in the solution. grams of H2O

2. Calculate the weight percent of CaCl2 in the solution. weight % CaCl2

3. Calculate the molality of CaCl2 in the solution. m CaCl2

4. Calculate the mol fraction of CaCl2 in the solution. (mol fraction CaCl2)

5. Calculate the mol fraction of Cl- ion in the solution. (mol fraction Cl-)

Relate the following structures, molecules, events/processes, etc. to transcription and to one another : 1. Introns 2. Exons 3. Eukaryotes 4. Prokaryotes 5. Euchromatin 6. Heterochromatin 7. Pre - mRNA (initial transcript) 8. Mature mRNA 9. Structural gene 10. Nuclear membrane

Specify reagents suitable for converting 3-ethyl-2-penteneto each of the following:

a) 2,3- Dibromo-3-ethylpentane

b) 3-Chloro-3-ethylpentane

c) 2-Bromo-3-ethylpentane

d) 3-Ethyl-3- pentanol

e) 3-Ethyl-2-pentanol

f) 2,3-Epoxy-3-ethylpentane

g) 3-Ethylpentane