A tau protein is being studied. It is believed to have a mass between 55,000 and 62,000 g/mol. You have been given the task of determining its actual molecular mass. If you assume a mass of 58,500 g/mol, and were to dissolve 5.00mg in 1.00mL water, calculate the freezing point depression, boiling point elevation, the vapor pressure change (from 23.76 Torr at 25C), the osmotic pressure, and the height of a column of water corresponding to this osmotic pressure. Which method would you use to experimentally determine the molecular mass of this polymer. Why?

1)

How many kJ of energy are required to transform 30.00 moles of solid benzene at -20.00 °C to

gaseous benzene at 140.0 °C?

2)

Consider He, CaS, CH4, LiF, CaO, diamond, H2O, CH3CH2OH, LiCl, and CH3OCH3. Arranged

in increasing melting point, these are:

Predict the products of the following reactions and then balance the equation. Make sure to put in the phases of the products. Pb(NO3)2 (aq) + Na3PO4 (aq) →

A. For the above equation, write the complete ionic and net ionic equations.

B. If you have a 2.5 M solution of lead (II) nitrate, and a 3.5 M solution of sodium phosphate, how much of the two solutions will you need to make 11.5 g of the product that precipitates?

C. To make the two solutions how many grams of each will you need?

D. What are the spectator ions and will be the final molarity of the compound made up of the spectator ions?

Which of the following bonds has the longest bond length?

Select one:

A. C-N

B. C-P

C. C-As

D. C-Sb

1. Draw the structure of the unbranched isomer of C5H11Br that is most reactive in an SN1 reaction.
Do not consider stereochemistry.
If there is more than one structure that fits the description, draw them all.

2. Draw the product you expect from the reaction of (S)-3-iodohexane with CH3S-. Be sure to show stereochemistry.

Please EXPLAIN your answer, do not just state the answer.

72) Which of the following compounds contains the longest carbon-carbon single bond?

A) allene

B) 1, 3-butadiyne

C) 1, 3-butadiene

D) propyne

E) ethane

1. Determine the oxidation numbers for all elements on BOTH sides of the following reaction 2Al(s) 6HCl(aq) -----------> 2AlCl3(aq) + 3H2(aq).

2. Students perform a reaction specified in the directions. A precipitate forms. Predict(circle) the precipitate in each of the following cases:

AgNO3(aq) + NaCl (aq) ------------------> AgCl + NaNO3

HgSO4(aq) + Na2S(aq) ----------> HgSO4 + Na2S

Ba(CH3COO)2(aq) + NaOH(aq) ---------------> Ba(OH)2 + 2NaCH3COO

A .845 M solution of glucose in water has a density of 1.0624 g/mL at 20 degree C what is the concentration of this solution in the following units. Assume 1 L of solution

a. mole fraction

b. mass percent

c Molality

For the diprotic weak acid H2A, Ka1 = 2.1 × 10-6 and Ka2 = 7.0 × 10-9. What is the pH of a 0.0700 M solution of H2A?

Balance the following equation by the method of oxidation-reduction showing all electron tranfers. Please show work.

___ H₂C₂O₄ + ____ KMnO₄ ---> ____ CO₂ + ____ Mn₂O₃ + ____ H₂O

Identify (a) the atom oxidized, (b) the atom reduced, (c) the reducing agent, (d) the oxidation half reaction, and (e) the reduction half reaction.

1. The isoelectric point of casein is 4.6. Milk has a pH of 6.6. What does prolein look like in milk, (overall negative -, overalll positive +, or neutral with both – and + charges)?

1) If you had not dried the solid, would the calculated percent yield have been higher, lower, or unchanged? Explain

2)Boron trichloride is prepared from the following reaction. 2B2O3 + 6Cl2 + 3C --> 4BCl3 + 3CO2 If 8.254g of B2O3 is mixed with 4.446g of Cl2 and 4.115g of C then answer the following questions.   

2a) What is the theoretical yield of boron trichloride in grams?

2b) How much of each of the excess reagents with remain once the reaction is complete? (report in grams)

3) If the yield of the reaction in question 2 is known to be only 73.42%, how much of each of the three reagents would you need to obtain 10.000g of boron trichloride?

I am so confused?? I included my data, the procedure and what we need to calculate. Dont know where to begin. Thank you!

Average mass of Pepto bismol tablets - 1.021

Mass in weighing boat = 10.080 g

Mass of emptied weighing boat = .003

subtract the two masses = 10.077

Measured mass of 2nd filter paper 0.116G

Watch glass 54.756 g

Obtain 10 pepto bismol tablets. Find the average mass of the 10 tablets and calculate the average mass/tablet.   Average mass of pepto bismol tablet = 1.021

Grind the tablets

Pour the contents into a weighing boat and find it mass.   10.080 g

Pour the contents of the weighing boat in a 250 ml beaker and find the mass of the weighing boat after it is emptied. Subtract the two masses for the mass of the ground tablets in the beaker. Mass of emptied weighing boat = .003          subtract the two masses = 10.077

Measure 100 ml of 2 M HCI into a graduated cylinder.

Add 20 ml of 2 M HCI to the powder and mix with a glass rod until it stops foaming.

Using a Buchner funnel, filter paper and a clean arm flash that has been rinsed with purified water, filter the the solution.

if the filtrate is cloudy, pour it back into the beaker and filter it through the same piece of filter paper again.

using your squeeze bottle, rinse the beaker with small amounts of purified water and pour into the funnel. This rinses the solids in the process.

Transfer the solution to 250mL to a volumetric flask.

Use a 25ml volumetric pipette to measure 50 ml of your solution into a beaker.

Measure 60 mL of 0.2 M Na3PO3 in a graduated cylinder and add to the beaker.

using a buchner funnel, filter paper and side arm flask, filter the solution and retain the solid. Filter this solution until clear.

Once your BiPO4 has been filtered, place the filter paper onto a pre weighed watch glass and place it where instructed to dry until next week.

The following week, obtain the mass of the BiPo4 precipitate.

1 Calculate the mass of pepto bismol tablets that were placed into your beaker in step 4 week 1

2 calculate the mass of dry BiP)4 precipitate by subtracting the watch glass and filter paper mass.

from the mass of precipitate, calculate moles of BiPO4 that were formed.

3 Using the moles found in (3) and the knowledge that each sample used 50 ml of solution find the concentration in moles/L of Bi3+ in solution before you added Na3PO4.

4 With the concentration calculated in (4) calculate the total number of moles of Bi in the 250 ml volumetric flask.

5 Knowing that each Bismuth subsalicylate molecule contains 1 bismuth atom (a 1:1 ratio), calculate the number of moles of bismuth subsalicylate you added to your original beaker and convert this to grams.

6 Divide grams of bismuth subsalicylate (6) by grams of pepto bismol used (1). This will give you an answer in units of g Bi-SS/g PB tablet.

7 Knowing your average mass per tablet, find the mass of Bi-SS tablet. Hint you have g Bi-SS g PB and you have g PB tablet.