@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 0.2212. 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.

@X@user.full_name@X@ @GMU: Which reactant in the reaction below is an acid (this one first in the answer) and which product is an acid?ClO-4 + H2SO4 → HClO4 + HSO-4

@X@user.full_name@X@ @GMU: The cell potential was -0.248 V at 25oC and a Sn4+(aq) concentration of 0.149 M. What was the hydronium ion concentration? The H2(g) pressure was 1 atm at 25oC.2H+(aq) + Sn2+(aq) → Sn4+(aq) + H2(g) Ecoell = -0.150 V

@X@user.full_name@X@ @GMU: What is the rate of consumption of A (M/s), if the rate of consumption of B is 0.287 M/s? Use the reaction below:3A + 2B + 4C → products

@X@user.full_name@X@ @GMU: Which product in the reaction below is a base (this one first in the answer) and which product is an acid?ClO-4 + HClO → HClO4 + ClO-

@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 0.1228. 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.

@X@user.full_name@X@ @GMU: What would the pOH be after addition of 9.97 mL of 0.1000 M NaOH to 25.00 mL of 0.1000 HA (a weak acid, Ka = 6.08e-4)?

@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 6.98e1 s when the initial concentration of NO2 was 2.99e-3 M. What is the rate constant for this reaction?2NO2(g) → 2NO(g) + O2(g)

@X@user.full_name@X@ @GMU: By how much would the rate of reaction (see below) change if the concentration of CH3CHO increased by a factor of 2.128. The rate law of this reaction is Rate = k3/2.CH3CHO(g) → CH4(g) + CO(g)

@X@user.full_name@X@ @GMU: The reaction below is an endothermic reaction. What would one have to do to shift the equilibrium to the right?SO2Cl2(g)→SO2(g) + Cl2(g)