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@X@user.full_name@X@ @GMU: Calculate the pOH of 110.06 mL of a buffer initially consisting of 0.1405 M N2H4 and 0.1691 M N2H5Br after addition of 0.0022 mol of HCl. Assume that no volume change occurs after addition of the acid. The Kb of N2H4 is 8.90e-7

@X@user.full_name@X@ @GMU: What is Kp for the reaction below, if Kc = 2.38e-5 at 146.4°C?3A(s) + 3B(g) → 2C(g)

@X@user.full_name@X@ @GMU: Uranium -238 decays in a series of steps to Pb-206. When the material is very old, one can treat the kinetics as a decay directly to Pb and the ratio of these two can be treated as a measure of the age of a rock. A rock containing 238U and 206Pb was examined to determine its approximate age. The molar ratio of 206Pb to 238U was 0.1461. Assuming no lead was originally present and that all lead formed remained in the rock, what is the age of the rock (in years)? The half-life of 238U is 4.50e9 yr.

John Schreifels @GMU: What is the change in mass of 71Ga when it is formed from protons, electrons and neutrons if the atom has a mass of  70.9247005 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 2.70 M-1s-1 at 449.91°C?NO2(g) + CO(g) → NO(g) + CO2(g)

@X@user.full_name@X@ @GMU: Initially there were equilibrium concentrations of 0.3554 M A, 0.2705 M B, and 0.1775 M C. Which change will cause the equilibrium to shift from left to right if the reaction is exothermic? Use the reaction below.6A(aq) → 2B(aq) +3C(aq) K = 0.547

@X@user.full_name@X@ @GMU: What phase(s) exist at point 1 in the phase diagram below?

@X@user.full_name@X@ @GMU: Which base listed below would be the best to creat a buffer having a pH of 8.2311?

@X@user.full_name@X@ @GMU: Determine the molality of a 6.563 wt % aqueous solution of NaF.

@X@user.full_name@X@ @GMU: What would the [H3O+] be after addition of 13.43 mL of 0.1000 M NaOH to 25.00 mL of 0.1000 HA (a weak acid, Ka = 5.55e-5)?