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:
| αIA = | 0.072 | αIB = | 0.306 |
| αIIA = | 0.760 | αIIB = | 0.036 |
Using this data, calculate the ratio between the relative concentrations of MR- and HMR in this solution.
In: Chemistry
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?
In: Chemistry
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?______________________________
In: Chemistry
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
In: Chemistry
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?
In: Chemistry
How does the vapor pressure of a compound determine its potential to be used as a fumigant?
In: Chemistry
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
In: Chemistry
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?
In: Chemistry
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.
In: Chemistry
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
In: Chemistry
In: Chemistry
7. (16 point) (a) The pH of a 1.00 L buffer solution containing
0.15 M HOCl and 0.15 M NaOCl is 7.52.
HOCl (aq) + H20 (l) ---> OCl- (aq) + H3O+ (aq)
(a) Calculate the pH change when 0.40 g of NaOH is added to 1.00 L
of a buffer solution containing 0.15 M HOCl and 0.15 M NaOCl.
Neglect any volume change. Ka of HOCl is 3.0 x 10-8.
(b) Calculate the pH change when 0.200 L of 0.100 M HCl is added to
1.00 L of a buffer solution containing 0.15 M HOCl and 0.15 M
NaOCl. Assume the total volume of the solution is 1.20 L. Ka of
HOCl is 3.0 x 10-8.
In: Chemistry
Nitrogen from gaseous phase is to be diffused into pure iron at
973 K. Surface is maintained at 0.1 wt% N, what will be the
concentration 1 mm from the surface after 10 hours? diffusion
coefficient at 700 C is 2.5E-11 m^2/s
Please show your work!
A) 0.46 wt%
B) 0.010 wt%
C) 0.1 wt%
D) 0.046 wt%
In: Chemistry
12. In a solution, when the concentrations of a weak acid and its conjugate base are equal,….
[A] the system is not at equilibrium
[B] the -log of the [H+] and the -log of the Ka are equal
[C] the buffering capacity is significantly decreased
[D] the buffering capacity is significantly increased
[E] All of the above are true.
13. The concentration of iodide ions in a saturated solution of lead (II) iodide is ________ M.
The solubility product constant of PbI2 is 1.4 x 10-8.
[A] 1.4 x 10-8 [B] 1.5 x 10-3 [C] 3.5 x 10-9 [D] 3.8 x 10-4 [E] 3.0 x 10-3
14. The solubility of lead (II) chloride (PbCl2) is 1.6 x 10-2 M. What is the Ksp of PbCl2?
[A] 4.1 x 10-6 [B] 1.6 x 10-5 [C] 3.1 x 10-7 [D] 5.0 x 10-4 [E] 1.6 x 10-2
15. The solubility of manganese (II) hydroxide (Mn(OH)2) is 2.2 x 10-5 M. What is the Ksp of
Mn(OH)2?
[A] 2.2 x 10-5 [B] 2.1 x 10-14 [C] 1.1 x 10-14 [D] 4.8 x 10-10 [E] 4.3 x 10-14
16. Which of these expressions correctly expresses the solubility-product constant for
Ag3PO4 in water?
[A] [Ag][PO4] [B] [Ag+][PO43−] [C] [Ag+]3[PO43−]
[D] [Ag+][PO43−]3 [E] [Ag+]3[PO43−]3
17. A solution of NaF is added dropwise to a solution that is 0.0166 M in Ba2+. When the
concentration of F- exceeds ________ M, BaF2 will precipitate. Neglect volume changes.
For BaF2, Ksp = 1.7 ⋅ 10-6.
[A] 1.0 x 10-2 [B] 1.0 x 10-4 [C] 5.1 x 10-5 [D] 2.5 x 10-3 [E] 2.8 x 10-8
18. A solution contains 2.3 x 10-4 M Ag+ and NaI solution is being added drop wise. What
is the minimum concentration of I- to begin precipitation of AgI? Ksp (AgI)= 8.3 x 10-17
[A] 8.32 x10-17 M [B] 2.51 x 10-17 M [C] 3.01 x 10-15
[D] 3.51 x 10-14 M [E] 3.61 x 10-13 M
In: Chemistry
1e. The formula for the compound name iodic acid:
Group of answer choices
1f. The name of the compound Cl2O3:
Group of answer choices
1g. The total number of valence electrons for molecule H2S:
Group of answer choices
1h. The molecular geometry of H2S:
Group of answer choices
1i. The polarity of molecule H2S:
Group of answer choices
1j. Which acid would dissociate partially in water to produce hydrogen ions?
Group of answer choices
In: Chemistry