Discuss capillary (zone) electrophoresis, micellar electrokinetic chromatography (MEKC) and capillary electrochromatography. Describe similarities and differences in working principle, injection, and separation. Discuss advantages and disadvantages of each of these techniques. Which compounds would you separate with each of these techniques?
1)Describe IN POINT FORM what happens when you raise the pressure of a sample of water from 0.004 atm to 40 atm at a constant temperature of 100 degrees celcius.
2)Describe IN POINT FORM what happens when you raise the temperature of a sample of water from -100 to +300 at a constant pressure of 40 atm.
From the data below, calculate the total heat (in J) needed to convert 0.535 mol of gaseous ethanol at 300.0°C and 1 atm to liquid ethanol at 25.0°C and 1 atm:
b.p. at 1 atm: 78.5°C
ΔH o vap : 40.5 kJ/mol
cgas: 1.43 J/g·°C
cliquid: 2.45 J/g·°C
6. What is the silver ion concentration in a solution prepared by mixing 389 mL of 0.391 M silver nitrate with 441 mL of 0.487 M sodium phosphate? The Ksp of silver phosphate is 2.8
Consider the combustion reaction of hydrocarbon.
CH + O2 -----> CO2 + H20
a. Write out the equilibrium expression for in terms of partial pressures?
b. In which direction will the reaction shift if temperature is increased? Briefly explain.
c. In which direction will the reaction shift if the volume is increased? Explain using the reaction quotient.
Calculate the atomic percent of tungsten in an alloy prepared with 56 grams of tungsten and 48 grams of aluminum. The atomic mass of tungsten is 183.85 g/mol and aluminum is 26.98 g/mol.
1. Calculate [H3O+] in the following aqueous solution at 25 C: [OH−]=1.1×10−9 M.
2. Calculate [H3O+] in the following aqueous solution at 25 C: [OH−]=2.4×10−2 M .
3. Calculate [H3O+] in the following aqueous solution at 25 C: [OH−]=6.2×10−12 M
then classify the solutions as acidic or basic.
We used FTIR-ATR to determine vinyl acetate from a glue stick using the internal standards method. We used the standards with 12, 18, 25, and 40% poly(ethylene-co-vinyl acetate). The peak height at 1020 cm^-1 is due to the vinyl acetate copolymer (our analyte) and the peak height at 720 cm^-1 is due to the polyethylene (the internal standard). Our unknown is a store-bought glue stick that is EVA-based.
We found the peak heights for the standards for the peaks on 720 cm^-1 and 1020 cm^-1. What I am aware of is that those are uncorrected peaks. How do you correct the peaks?
After that, we plan on taking the ratio of the concentration in percentages and the ratio of absorbances and plot them, using it as a calibration curve.
1. At 1 atm, how much energy is required to heat 91.0 g of H2O(s) at –24.0 °C to H2O(g) at 171.0 °C?
2.When 1518 J of heat energy is added to 48.6 g of hexane, C6H14, the temperature increases by 13.8 °C. Calculate the molar heat capacity of C6H14.
3.A 56.90 g sample of a substance is initially at 21.3 °C. After absorbing 1615 J of heat, the temperature of the substance is 146.8 °C. What is the specific heat (c) of the substance?
pH concentration (M) mL
7.8 1.0 100.00
Where Stotal=moles (A) + moles (B)
Ptotal=mol (H2PO4-)+mol (HPO42-)
PH=pKa + log (moles B/molesA)
Determine the Mass of Each Component
Recall that buffers are formed from conjugate acid/base pairs. Using the information given about your assigned buffer, determine how much of each component (acid and base) you will need in order to prepare it in the lab. (This will require a system of equations because there are two “unknowns.”)
Note: the conjugate acid in this case is H2PO4−, and the conjugate base is HPO42−.
1. Using equation (3) in your lab manual, solve for the ratio of (moles B/moles A).
2. From the ratio, solve for the moles B in terms of moles A. (Hint: you are not solving for the actual number of moles B at this point, you are only solving for the relationship of B to A.)
3. Using your concentration and volume, solve equation (1) in the lab manual for Stot.
4. Stot is the total moles of solute components (the sum of your acid and base combined). Using equation (2) in the lab manual, and substituting your answer to question 2 in for “moles B,” solve for the quantity of moles A.
5. Solve for the quantity of moles B by inserting your numerical value for moles A into the relationship found in question 2.
6. Determine how many grams of each component must be measured out in order to make the buffer solution. Note that the conjugate acid comes as a solid of NaH2PO4H2O, and the conjugate base comes as a solid of Na2HPO47H2O.
Determine pH Values of a Buffered System
7. Suppose that you pour half of your buffer solution into a separate beaker and add 1.00 mL of 0.103 M HCl into it. What pH would you expect to measure with a pH probe? Show all work. (Hint: Is HCl an acid or a base? Is it strong or weak? How would it affect your buffer components?)
8. Suppose you add 1.00 mL of 0.098 M NaOH into the other half of your buffer solution. What pH would you expect to measure with a pH probe? Show all work. (Hint: Is NaOH an acid or a base? Is it strong or weak? How would it affect your buffer components?)
Determine pH Values of an Unbuffered System
9. What pH would you expect to measure if you placed 52.5 mL of DI water into a beaker and added 1.00 mL of 0.103 M HCl? Show all work.
10. What pH would you expect to measure if you placed 51.3 mL of DI water into a beaker and added 1.00 mL of 0.098 M NaOH? Show all work.
Define the following terms and draw one example of each using organic molecules:
Van der Waal's non-polar interactions, Dipolar interactions, Hydrogen Bonding.
What is the function of the silica gel in TLC experiment?
We used Chloroform:Isopropyl alcohol and Ethyl acetate:Acetic acid for solvents in TLC lab to get Rf values of aspirin and ibuprofen. What difference does it make trend wise? Also explain the observed trend in terms of the chemical structure and molecular interactions involeved between the analyte, solid phase and the mobile phase.
These are the results I got.
Chloroform:Isopropyl alcohol --> Rf of Aspirin=0.68 and Ibuprofen=0.78
Ethyl acetate:acetic acid --> Rf of Aspirin=0.79 and Ibuprofen=0.85
Thank you so much!
Silver iodide is a very insoluble compound. Please give reasons for compounds like silver sulfate or silver chloride to be insoluble that relate to ionic radius.
I want to know the whole C5H10 structures that can be formed (chain, ring...etc) including streoidimers. Thanks.