outline a lab experiment which could be done in order to determine delta H, delta G and dellta S of dissolution of Urea
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Einstein predicted that the mean squared displacement of small particles due to diffusion (random motion, executed in small, discrete steps) would increase linearly with time. Prove it in a simple way.
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1) Write a chemical equation describing the condensation process for N2 and a chemical equation describing the freezing process for N2. For each process discuss the change in enthalpy and entropy that occurs. For each process describe the conditions (in terms of temperature) that support a thermodynamically favorable change, and the conditions that do not support a thermodynamically favorable change.
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For 550.0 mL of a buffer solution that is 0.185 M in CH3CH2NH2 and 0.175 M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.020 mol of HCl. Express your answers using two decimal places separated by a comma.
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In paper chromtography, what is the nature of the attractions between the stationary phase (cellulose) and the moving phase (hydrochloric acid/water/acetone) and the species ( Zn2+, Co2+, Cu2+, Cd2+ , Fe3+, and Ni2+ in two unknown solutions) being separated, in particular what affects the Rf values and how?
Note: Filter paper (Whatman #1) serves as the stationary phase, and the mobile phase consists of a mixture of acetone and 6 M hydrochloric acid. A single spot of the mixture to be analyzed is applied near one edge of a sheet of filter paper. A spot of solution containing each of the cations that might be in the unknown mixture is also placed near the edge of the same sheet for comparison. The treated strip is then placed in a covered jar or beaker (which acts as a developing chamber) containing a shallow layer of the solvent mixture (see Figure 3). Since filter paper is very permeable to the solvent, the solvent begins to rise up the strip by capillary action. The various spots on the developed chromatogram will be highlighted by treatment with several chemical reagents to enhance their color. The reagents to be used are ammonia, dimethylglyoxime (DMG), and 8–hydroxyquinoline (oxine).
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What is the pH of a solution made by mixing the following?
20.0 mL of 0.10 M HClO (Ka = 3.0x10-8)
20.0 mL of 0.10 M KOH
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Calculate (using bond energies) the heat of reaction (per mole of CO, in KJ/Mol) for the combustion of CO into CO2. Balance and do not round final answer
Calculate (using bond energies) the heat of reaction (per mole of C2H2 in KJ/Mol) for the combustion of C2H2 into CO2 and water. Balance and do not round final answer
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Calculate the pH of the following dilute solutions:
(a) 3.42x10-8 M hydroiodic acid, HI.
(b) 5.77x10-9 M KOH.
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A buffer solution is made by dissolving 0.230 moles of sodium hypochlorite in 1.00 L of 0.220 M hypochlorous acid (HClO). What is the pH of the solution after 0.0100 moles of sodium hydroxide is added? (The Ka of HClO is 2.9
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Using activity coefficients (find them with debye-huckel equation), calculate molar solubility of Zn(OH)2 in
c) a mixture of 40.0mL of 0.250M KOH with 60.0mL de ZnCl2 0.0250M (answer should be 2.8*10^-13)
d) a mixture of 20mL 0.100M KOH and 50.0mL of 0.0250M ZnCl2
Note: if you attempt this question please solve both parts (a and b) and show your work or else your attempt will be rated as wrong/reported
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Show reactions for preparing each of the following compounds by the Grignard method:
3-pentanol
3-methyl-3-pentanol
Hexanoic acid
1-phenyl-1-propanol
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Calculate the pressure in cm H2O exerted in the closed end of an apparatus if the atmospheric pressure is 720.0 torr and the height of the water coloumn is 22.3cm.
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1.) You are given a sample of an unknown hydrate of CaSO4. The average values of the data collected and recoded in your laboratory notebook where as follows: Mass of empty crucible 31.138 g Mass of crucible and sample before heating 31.457 g Mass of crucible and sample after heating 31.436 g Calculate the formula of the CaSO4 hydrate.
2.) Sodium hydroxide pellets are very hygroscopic. Describe what happens chemically when a cover is left off a bottle of NaOH pellets. (Hint: Carbon dioxide reacts with NaOH.)
3.) A 120.0 mg sample of a lead acetate hydrate, Pb(C2H3O2)2 xH2O was heated to drive off the waters of hydration. The cooled residue weighed 103.0 mg. Calculate the value of x in the acetate formula.
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Predict the standard cell potential and calculate the standard reaction Gibbs free energy for galvanic cells having the following cell reactions:
a) 3 Zn(s) +2Bi^3+(aq)--> 3 Zn^2+(aq) + 2Bi(s)
b) 2 H2(g) + O2(g)--> 2 H2O(l) in acidic solution
c)2 H2(g) +O2(g)--> 2 H2O(l) in basic solution
d) 3 Au+(aq) --> 2 Au(s) + Au^3+ (aq)
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Achiral compound X has the formula
C8H17Br. Y,
C8H17Cl, is chiral.
X undergoes base-promoted E2 elimination to give a
single alkene product Z. Under similar conditions
Y produces a mixture of alkenes, including
Z.
Catalytic hydrogenation of Z affords
2-methylheptane. Propose structures for X and
Y.
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