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@X@user.full_name@X@ @GMU: How much time in days would it take for a 1.7139 g sample of 14C to decay to a mass of 0.6940 g if it has a half-life of 1.807e11 s.

@X@user.full_name@X@ @GMU: NO2 at 383°C decomposes to form NO and O2 according to second order kinetics (see reaction below). The half-life for this reaction was measured to be 5.40e1 s when the initial concentration of NO2 was 3.86e-3 M. What is the rate constant for this reaction?2NO2(g) → 2NO(g) + O2(g)

@X@user.full_name@X@ @GMU: What is the balanced reaction at the cathode for the following galvanic cell?Cu(s)| Cu2+(aq) || Sn2+(aq) | Sn(s)

@X@user.full_name@X@ @GMU: What is the equilibrium concentration of H3O+ in 0.1321 M H2S? See reaction belowH2S + H2O → HS- + H3O+ Ka = 9.100×10-8

@X@user.full_name@X@ @GMU: NO2 at 383°C decomposes to form NO and O2 according to second order kinetics (see reaction below). The half-life for this reaction was measured to be 3.46e1 s when the initial concentration of NO2 was 6.03e-3 M. What is the rate constant for this reaction?2NO2(g) → 2NO(g) + O2(g)

@X@user.full_name@X@ @GMU: What must the reaction quotient Q be, if the free energy is -270.159 kJ at 25.0oC?C2H2(g) + 2 H2(g) → C2H6(g) ΔGo = -242.202 kJ.

@X@user.full_name@X@ @GMU: Calculate the [H3O+] of 107.61 mL of a buffer initially consisting of 0.1647 M CH3(CH2)2CH2NH2 and 0.1877 M CH3(CH2)2CH2NH3NO3 after addition of 0.0020 mol of HCl. Assume that no volume change occurs after addition of the acid. The Kb of CH3(CH2)2CH2NH2 is 4.10e-4

John Schreifels @GMU: What would the pH be after addition of 12.60 mL of 0.1000 M NaOH to 25.00 mL of 0.1000 HA (a weak acid, Ka = 2.95e-4)?

@X@user.full_name@X@ @GMU: What is the pH of 3.22e-3 M HClO3 ?

@X@user.full_name@X@ @GMU: When 10.70 g of aspirin was dissolved in 107.9 g of benzene, the freezing point was 275.8 K. What is the formula mass of this compound? The freezing point depression constant for benzene is 5.12 (°C*kg)/mol. The melting point and boiling points are 5.50°C and 80.10°C, respectively.