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John Schreifels @GMU: What is the total entropy change at 25oC for the reaction below, if the standard entropies of reactants and products are So(C(gr)) = 5.74 J/mol*K, So (H2(g)) = 130.68 J/mol*K, and So (C3H8(g)) = 270.2000J/mol*K and the heat of formation of C3H8(g)) is -103.8500 kJ/mol.C3H8(g) → 3C(gr) + 4H2(g)

@X@user.full_name@X@ @GMU: Determine the molality of a 5.664 wt % aqueous solution of NaF.

@X@user.full_name@X@ @GMU: By how much would the rate of reaction (see below) change if the concentration of Cl2 increased by a factor of 1.557. The rate law of this reaction is Rate = k[CHCl3][Cl2]1/2.CHCl3(g) + Cl2(g) → CCl4(g) + HCl(g)

@X@user.full_name@X@ @GMU: Determine the molality of a 7.450 wt % aqueous solution of LiI.

@X@user.full_name@X@ @GMU: What is the temperature at which the reaction below becomes spontaneous, if the standard entropies of reactants and products at 25oC are So (C(gr)) = 5.74 J/mol*K, So(H2(g)) = 130.68 J/mol*K, and So (C8H10(g)) = 368.9900J/mol*K and the heat of formation of C8H10(g)) is 29.8000 kJ/mol?8C(gr) + 5H2(g) → C8H10(g)

@X@user.full_name@X@   @GMU: When 0.4026 g of citric acid was dissolved in 109.3 mL of water, the osmotic pressure at 20.52°C was 0.4621 atm. What is the formula mass of this compound?

John Schreifels @GMU: What is the change in mass of 93Nb when it is formed from protons, electrons and neutrons if the atom has a mass of 92.9063772 amu? The masses of the proton, electron and neutron are 1.00728 amu, 0.000549 amu and 1.00867 amu, respectively.

@X@user.full_name@X@ @GMU: What is the activation energy (in kJ/mol) for the reaction below if the rate constants are 1.300 M-1s-1 at 427.00°C and 2.42 M-1s-1 at 446.39°C?NO2(g) + CO(g) → NO(g) + CO2(g)

@X@user.full_name@X@ @GMU: LiF has a face-centered cubic unit cell in which the F- anions occupy corners and face centers, while the cations fit into the hole between adjacent anions. What is the radius of Li+ if the ionic radius of F- is 136.0 pm and the density of LiF is 2.635 g/cm3?

@X@user.full_name@X@ @GMU: What is the standard free energy change for the following cell?3Cu2+(aq) + 2Cr(s) → 3Cu(s) + 2Cr3+(aq) Ecoell = 1.080V