Hi, I'm having trouble solving this worksheet. FYI, I'm in grade 11 AP chem.
Cr2O7(2-) + 14H(+) + 3C2O4(2-) --> 2Cr(3+) + 7H2O + 6CO2
a) suggest two methods to measure the rate of this reaction.
For this question I said, method 1) reactions that produce a gas and method 2) reactions that produce or consume ions.
b) If the number of moles of each reactant consumed after one minute was consumed, which species would be consumed the least? the most?
c) if 0.06mol/L of Cr(3+) ions was produced in the first two minutes calculate the average rate of reaction in mol/Ls.
I tried using change in C/time elapsed (s) but seems like I need to solve b first to solve c.
d) what would be the corresponding rate of dichromate consumption during the same period.
a) My personal opinion is that your answer is in general for questions of this type. I think the question wants specific answers for this specific reaction. I would answer that one method would be to measure the amount of CO2 produced and a second method would be to measure the amount of Cr2O7^2- consumed OR measure the amount of oxalate consumed OR to measure the change in pH (which probably is the easiest to do for method 2.
(b) The least is dichromate. The most is H^+
(c) If the problem is asking just for average rate then in terms of Cr^3+ I don't see why any other information is needed. Avg rate = (1/n)*dCr^3+/dt = 1/2*0.06/2 = ? in M/min. Convert that to seconds.
(d) -1/2 that for Cr^3+. The minus sign because you're DECREASING reactants.