A compound containing 3 mCi of Sulfur-35 (half-life = 87 days)is stored in a laboratory. How much radioactivity will there be after 348 days?

1.

0.1875 mCi

2.

0.75 mCi

3.

0.375 mCi

4.

0.1875 mCi

5.

0.094 mCi

Calculate the concentrations of all species in a 1.38 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8.

These are the following concentrations that I need to find.

[Na+]

[SO3^2-]

[HSO3-]

[H2SO3]

[OH-]

[H+]

Please show me how to solve this problem. Anything help is greatly appreciated. Thank you.

How were the nanoparticles multiplexed?

Zinc, Zn, adn iodine, I2, react to form zinc(II) iodide, ZnI2 ( the reactants and the product are all solids at room temperature).

a. write a balanced chemical reaction for this process.

b. suppose that 50.0 g of zinc and 50.0 g of iodine are used to form zinc(II) iodide.

1. assuming that the reaction goes to completion, which element will be totally consumed in the formation of the zinc(II) iodide?

2. what is the limiting reagent?

3. how many grams of zing(II) iodide can be produced?

4. how many grams of the excess element remain unreacted?

1. What happens to the working electrode when the electrolyte concentration is changed?

2. Explain absorption emission through the Jablonski Diagram.

At 1 atm, how much energy is required to heat 91.0 g of H2O (s) at-16.0 degrees C to H2O (g) at 141 degrees celsius?

1) When 10ug of an enzyme (MW 50,000) is added to a reaction mixture containing its substrate at a concentration one hundred times the Km, it catalyzes the conversion of 75umol of substrate into product in 3 min. What is the enzyme's turnover number?

2) You want to load 15g of protein in 10L into one of the 12% polyacrylamide gel well. The protein needs to be in 1X buffer and in a total volume of 0.100 ml. You are given a 4.5 mg/ml protein solution, a 20X sample buffer, and distilled water. How much of each would you mix together to make required volume?

3) The Km of an enzyme of an enzyme-catalyzed reaction is 6.5uM. What substrate concentration will be required to obtain 45% of Vmax for this enzyme?

A protein assay requires the reaction of the protein solution with a protein-binding dye for one minute, followed by measuring the absorbance of the protein-dye complex at 505 nm. The absorbance data for four standard protein solutions and the blank is provided in the table below. The absorbance of each solution was measured three times. Construct a calibration curve using the data in the table, and find the slope (m), intercept (b), and their respective standard deviations using the method of least squares. Note that the calibration curve will be created from absorbance values corrected for the absorbance of the blank and not the raw data in the table (including individual blank values). When creating the calibration curve, do not use the average absorbance at each protein concentration. Instead, use each data point separately, meaning there will be three data points at each protein concentration, for a total of 15 points (including each individual blank value).

m= 1.012 +/- ?

b= ? +/- ?

Calculate the concentration and uncertainity of a protein solution that produced an averge absorption of 0.470 when measured three times.

number = ? +/- ?

1) If a block of wood has the dimensions of 50.0cm x 50.0cm x 45.0cm.

What is it's volume in Liters? (Give answer in correct significant digits)

2) If one kilogram is equal to 2.2 pounds:

      a.   What is the mass of a 5.0 lb bag of sugar?

1) Answer the following the questions regarding an acetic acid buffer solution.

a) A solution was prepared by dissolving 0.024 moles of acetic acid (HOAc; pKa =4.8 ) in water to give 1 liter of solution. What is the pH?

b)Then 0.009 moles of sodium hydroxide (NaOH) was added in to the solution. What is the pH of the solution? (In this problem, you may ignore changes in volume due to the addition of NaOH)

c)Additionally, 0.015 moles of NaOH is then added to the solution (2). What is the pH of the solution?

Complete and balance each equation. If no reaction occurs, write NOREACTION.

a) NaNO3(aq)+KCl(aq)?

b) NaCl(aq)+Hg2(C2H3O2)2(aq)?

c) (NH4)2S(aq)+SrCl2(aq)?

d) Al2(SO4)3(aq)+AgNO3(aq)?

Thanks

Part A What mass of calcium can be produced by this process if a current of 6300 A is applied for 39 h ? Assume that the electrolytic cell is 65 % efficient. Part A What mass of calcium can be produced by this process if a current of 6300 A is applied for 39 h ? Assume that the electrolytic cell is 65 % efficient. Part B What is the minimum voltage needed to cause the electrolysis?

Part B

How many minutes are needed to plate out 22.00 g Mg from molten MgCl2, using 3.00 A of current?

Calculate ΔH∘ in kilojoules for the reaction of acetylene (C2H2) (ΔH∘f=227.4kJ/mol) with O2 to yield carbon dioxide (CO2)(ΔH∘f=−393.5 kJ/mol) and H2O(g) (ΔH∘f=−241.8kJ/mol), a reaction which is supplied by the industrial gases industry for oxyacetylene gas welding and cutting due to the high temperature of the flame.

2C2H2(g)+5O2(g)→4CO2(g)+2H2O(g)

Express your answer using one decimal place.