1. What is Rf value? List three factors that affect the Rf value.
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Given the Sample Mass (g) is 0.2254 and AgCl Mass (g) is 0.5295, find the percent chloride.
[Note: Atomic Mass of Cl is 35.4527g and the Atomic Mass of Ag is 107.868.]
Please show calculations.
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1) At a pressure of 760 torr, formic acid (HCOOH; boiling point = 100.7 oC) and water (H2O; boiling point = 100.0 oC) form an azeotropic mixture, boiling at 107.1 oC, that is 77.5% by mass formic acid. At the boiling point of the azeotrope (107.1 oC), the vapor pressure of pure formic acid is 917 torr, and that of pure water 974 torr. If the solution obeyed Raoult's law for both components, what would be the vapor pressure (in torr) of formic acid at 107.1 oC?
2) If the solution obeyed Raoult's law for both components, what would be the vapor pressure of the water (in torr) at 107.1 oC?
3) If the solution obeyed Raoult's law for both components, what would be the total vapor pressure (in torr) at 107.1 oC?
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10. What is the [CH3COOH ]/[CH3COO– ] ratio in an acetic acid/sodium acetate buffer at pH = 4.90? (Ka = 1.8 x 10–5 )
a. 0.31
b. 0.70
c. 1.45
d. 2.41
e. 4.90
11. How many grams of NaCH3COO should be added to 250 mL of 0,100 M CH3COOH when the above solution is prepared?
a. 0.431 g
b. 2.95 g
c. 5.66 g
d. 1.43 g
e.11.9 g
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| Be sure to answer all parts. At 430 ° C, the equilibrium constant (KP) for the reaction
is 1.5 × 105. In one experiment, the initial pressures of NO, O2, and NO2 are 7.4× 10−3 atm, 4.2× 10−2 atm, and0.20 atm, respectively. Calculate QP and predict the direction that the net reaction will shift to reach equilibrium.What is QP for the experiment? In which direction will the system proceed to reach equilibrium?
|
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Compare and contrast all 4 types of distillation
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What change in pH should be observed if 10.0 mL of 0.100 M NaOH is added to 100 mL of a buffer that is 0.100 M in CH3COOH and 0.100 M in NaCH3CO2? Ka for acetic acid is 1.8 x 10-5.
If you can explain step by step that would be awesome!
In: Chemistry
Sodium hypochlorite (NaClO) is the active ingredient in household bleach. HClO has a Ka of 4.0 x 10-8 . You are titrating 30.0 mL of 0.10 M NaClO solution using 0.30 M HCl solution.
1) What is the pKa of HClO and the Kb of ClO- ?
2)What volume of the HCl solution (in mL) needs to be added to reach the equivalence point in this titration experiment? Show your work.
3)What volume of the HCl solution (in mL) needs to be added to adjust the pH of the starting solution to 7.40?
4) At the equivalence point, would you predict the pH to be acidic, basic, or neutral? What is the exact pH of this solution at the equivalence point? Express your answer to two decimal places. Show your work
In: Chemistry
Consider the reaction that you did to deprotonate vanillin using sodium hydroxide. If the pKa of vanillin is about 7.4, what is the equilibrium constant for the reaction of vanillin with sodium hydroxide to make the conjugate base of vanillin?
Write out the balanced equation, add arrows to show the mechanism of the reaction, and show your work/calculation(s).
In: Chemistry
In: Chemistry
In: Chemistry
Conformational analysis of a molecule was performed using a global-optimisation method where the energy was evaluated using Hartree-Fock (HF) theory. The binding energy of the low-energy conformers with a host complex was then calculated using the same level of theory. It was found that the lowest-energy conformer matched well with a known X-ray crystal structure but the binding energy with the host molecule was far too small.
(i) Define the term conformer.
(ii) Explain the general principles of global optimisation of a molecule and why global optimisation is challenging to perform.
(iii) Summarise the main contributions and terms that Hartree-Fock theory captures.
(iv)Explain why the low-energy conformers might be reasonably modelled by HF theory.
In: Chemistry
The energies of the ? MOs obtained from Hückel MO theory for ? sp2 hybridised carbon atoms forming a linear chain are given by:
?? = ? + 2?cos ( ?? ? + 1 )
where ? is the energy level (? = 1,2, … , ?) in order of increasing energy.
(i) Give the values of ? for the HOMO and LUMO in butadiene.
(ii) The energy required to promote an electron from the HOMO to the LUMO of butadiene was measured to be 309 kJ/mol. Determine the value of ?
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2Cu2+ + 4KI → 2CuI + I2 + 4K+ (rxn 1)
I2 + 2Na2S2O3 → 2NaI +
Na2S4O6 (rxn 2)
10.0 mL of a Cu2+ solution of unknown concentration was placed in a 250 mL Erlenmeyer flask. An excess of KI solution was added. Indicator was added and the solution was diluted with H2O to a total volume of 75 mL. The solution was titrated with 0.20 M Na2S2O3. The equivalence point of the titration was reached when 14.45 mL of Na2S2O3 had been added. What is the molar concentration of Cu2+ in the unknown solution?
In: Chemistry
How do you determine if an element or compund is electron rich? please provide examples.
In: Chemistry