## please answer usgreenspun.com : LUSENET : UR General Chemistry : One Thread |

ok, i am having trouble with the problems that are in tabular form. in one column there is number of atoms and in the other column there is time measured in days. the initial concentration is given the concentrations and days are as follows: time #0f atoms (initial time(t=0), 14182)( 85.8, 221) (114.4, 55) (143, 13) the first number time(days) the second number is # of atoms this is problem number five insection 1 of topic 15. this question is asking for the half-life(in days). the other problem is structured inthe same format; it is as follows: time(seconds) concentration (initial yime(t=0),.204) (72.9,.152) (145.8,.114) (218.7, .085) (291.6 .063)the first number is time(seconds)and the second numebr is concentration this question is also asking for the half-life(in seconds). also, this is a first order decay. this is problem number 9 of section 1 in topic 15.A simple explanation of these problems would really be helpful. I have tried using the formula for the half-life of a first order, but it simply is not working. Could someone explain this problem to me?

Also, will i be given credit for a problem that the computer says is correct, but does not recorded? i have been complaining about this problem for several days, and i haven't gotten an answer. i don't think that it is fair that i get the problem correct according to the computer, but since it is not recorded i don't end up getting any extra credut for some computer glitch. please respond this time concerning this problem.

thanks!!!!!!!!

-- Ms. Tara Marie Wilson (tw002i@mail.rochester.edu), April 07, 2000

Answers I am having the exact same problem as Tara.

-- Kelly Wentworth (kw004i@mail.rochester.edu), April 07, 2000.

-- Anonymous, April 07, 2000

While you're at it, i was wondering if you could explain the answer to 19, section three, number 3. I get an answer, and i am pretty sure it is right, but i do not know how to enter such a big number into calm.sk

-- Anonymous, April 07, 2000

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