[Aztex6]

Hey guys! I'm taking a course called Ecotoxicology and my professor gave everyone in class a homework assignment on general chemistry. The problem is I'm a junior and I took general chemistry courses during my freshman year and so I forgot a lot of things. The second problem is that my professor didn't even do any example problems in class and the book doesn't have any practice problems either. So, he basically told us to just do it and a lot of people in my class never took chemistry. So, on to the homework.

Question 2. Consider a solution that contains Cu2+ and Cl-. Given the log K for the formation of CuCl+ is 0.43 and the following data: total Cu in the solution = 2.5x10^3 M
equilibrium Cl-concentration = 10^-2M
-3 a. calculate concentrations of all Cu species (Cu2+, CuCl+) at the equilibrium state (25 points) b. what percent of Cu is not complexed? (15 points) Cu2+ + Cl-  CuCl+ K = [CuCl+]/[Cu2+][Cl-]

Question 2: The way I tried to do this problem is by plugging in the given numbers for Copper and Chlorine and I plugged 10^0.43 for K. So I multiplied both given concentration values for those elements and then I multiplied that with my K to get a value that was very wrong for the concentration of copper chloride. So, would an ICE table work to determine the concentrations of copper and chlorine at the equilibrium state? For the second part of the question I have no idea what they mean by "complexed" and so I don't know how to approach the problem.

Question 3: In 2011 there was a nuclear accident due to earthquake in Japan. A lot of radiation was emitted into the environment that led to evacuation of people around the area. However, people can return then the concentration of radioisotopes decrease to levels that are not harmful to humans. How many half-life would it take for the radioisotopes to decrease their initial concentrations to 3% (97% are gone).

For question three the professor said that the answer should equal 5 half lives. I tried to solve this by doing ln of 1/2 divided by -0.03 but it didn't give me 5. Then I tried to do ln of 1/2 divided by 0.97 but I didn't get 5 either.

Thank you so much!

[Borek]

Complexed - combined with Cl^-. CuCl⁺ is a complex (https://en.wikipedia.org/wiki/Coordination_complex)

Yes, ICE table should lead you in a correct direction.

[tex]N=N_0e^{- \frac t \tau}[/tex]

Just solve for t.