Which of the following reactions is/are redox reactions?  You may select more than one reaction.

In the body, mercury's toxic effects are known to result from its ability to disrupt and insert into S-S bonds in critical enzymes. Fish, particularly tuna, which contain high levels of methylmercury are frequently found to also have high levels of selenium. Given the low rate of mercury poisoning even in populations where large quantities of fish are consumed, this has led some to speculate that selenium serves to protect against mercury poisoning. Explain the chemical basis for this theory

An industrial wastewater contains a total cyanide concentration of 10-3M and a total nickel concentration of 210-4M. Calculate the concentrationof all species (HCN, CN-, Ni2+, and all cyanide and hydroxy complexes of nickel) at pH 9.0. State and verify all assumptions.

A pH 3.30 buffer is prepared from iodoacetic acid ICH₂COOH (pK_a = 3.175), and sodium iodoacetate, ICH₂COO^-Na⁺ . If ionic strength of the buffer solution must not exceed 0.200 M, what are the maximum concentrations of the two components that could be used?

What volume of KOH (conc = 1.850 M), could be added to 50.00 mL of the buffer solution of part (a), before the pH would increase to 4.000?

1. Compare the advantages and disadvantages of each pH method (i.e. cost, ease of use- time it takes to set up and take a pH measurement) including accuracy and precision of each method.

2. draw a diagram labeling the two silver/ silver chloride reference electrodes, glass membrane, and porous frit.

3. show how a charge is built up and produces a voltage that is measured.

Suppose that a student collects the following spectrophotometric data to determine the relative concentrations of HMR and MR in solution:

The abosorbance at 425 nm was measured to be 0.280 and at 520 nm was 0.720, the slopes corresponding to standard Beer's Law plots were as follows:

Using this data, calculate the ratio between the relative concentrations of MR^- and HMR in this solution.

You are trying to establish the IgG response from a recently vaccinated individual, where it will be important to know how much IgG they have both before and after the vaccination. You start with two samples of 8 mL of blood, one from before vaccination and one after. You use an affinity chromatography technique to remove just the IgG (ε = 1.35 g-1L cm-1). You end with a 2 mL sample of each. The pre-vaccinated sample has an A280 reading of 0.85, and the post-vaccinated sample has an A280 reading of 0.202 with a 10-fold dilution (both with a 1 cm path length).

a) How many micrograms of IgG were in each of the original blood samples?

b) What fold change in IgG amounts was seen after vaccination?

You have evaluated the theoretical pI of Our Protein Of Interest (OPOI), based on its amino acid sequence, to be 6.4. You select a working pH of 8.0 and will use what type of ion exchange?______________________________

A sample of 10.00 g of sodium reacts with oxygen to form 15.02 g of sodium oxide (Na₂O) and sodium peroxide (Na₂O₂). Calculate the percent composition of the mixture.

___% Na₂O

___% Na₂O₂

You purified the plasmid from an overnight cell culture and dissolved the plasmid DNA in 100 μL 0.1M Tris buffer (pH8). To quantify the plasmid, you took an absorbance measurement at 260 nm of a 1:50 dilution sample. The absorbance was 0.35. What is the concentration of the undiluted plasmid in micrograms per mL?

How does the vapor pressure of a compound determine its potential to be used as a fumigant?

Urea (NH₂)₂CO is prepared by reactign ammonia with carbon dioxide. The byproduct is water. 637.2g of ammonia are reacted with 787.3g of carbon dioxide.

A) write a balanced equation

B) Determine which of the reactants (ammonia or carbon dioxide) is a limiting reactant. Show calculations to support your choice

C) Which of the two reactants should you use to calculate the theoretical yield (=the maximum amount possible) of urea. Explain why

A 70.0mL sample of 1.0 M NaOH is mixed with 44.0 mL of 1.0 M H2SO4 in a large Styrofoam cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 23.9 Celcius. After adding the NaOH solution to the coffee cup, the mixed solutions are stirred until reaction is complete. Assume that the density of the mixed solutions is 1.00 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g celcius), and that no heat is lost to the surroundings. The deltaHrxn for the neutralization of NaOH with H2SO4 is -114 kJ/mol H2SO4. What is the maximum measured temperature in the Styrofoam cup?

The x coordinate of an electron is measured with an uncertainty of 0.200 mmmm . What is vxvxv_x, the x component of the electron's velocity, if the minimum percentage uncertainty in a simultaneous measurement of vxvxv_x is 1.00 %% ? Use the following expression for the uncertainty principle:

ΔxΔpx≥ℏΔxΔpx≥ℏ,

where ΔxΔx is the uncertainty in the x coordinate of a particle, ΔpxΔpx is the particle's uncertainty in the x component of momentum, and ℏ=h2πℏ=h2π, where hh is Planck's constant.

Express your answer in meters per second to three significant figures.

The correct answer is 57.9 m/s

part B

Repeat Part A for a proton.

Express your answer in meters per second to three significant figures.

A patient needs to be given exactly 500 mL of a 5.0% (w/v) intravenous glucose solution. The stock solution is 65% (w/v). How many milliliters of the stock solution are needed to prepare the fluid for the IV bag?

Which equation will determine how much water is needed to prepare the 5.0% (w/v) glucose solution?

a.) Volume of stock solution needed Volume given to patient (500 mL)

b.) Volume given to patient (500 mL) / Volume of stock solution needed

c.) Volume of stock solution needed / Volume given to patient (500 mL)

d.) Volume given to patient (500 mL) – Volume of stock solution needed