What are the relative and absolute uncertainty in the calculated solubility of AgX?. A chemist obtained the following data for percent lindane in the triplicate analysis of an insecticid
Trang 1Analytical chemistry
Semester II, 2020-221
1
HOMEWORK # 1 Due date: 11/3/2021
1 (30 pts) The solubility product Ksp for the salt AgX is (4.0±0.4)×10-8, and the molar solubility is square root of the Ksp What are the relative and absolute uncertainty in the calculated solubility of AgX?
2 (30 pts.) A chemist obtained the following data for percent lindane in the triplicate analysis of an insecticide preparation: 7.23, 6.95, and 7.53 Calculate the 95% confidence interval for the mean for the three data, assuming that:
a the only information about the precision of the method is the precision for the three data
b on the basis of long experience with the method, it is believed that s σ = 0.28% lindane
3 (40 pts.) The homogeneity of chloride level in a water sample from a lake was tested by analyzing portions from the top and from near bottom of the lake, with the following results in ppm Cl
a (15 pts.) Apply the t-test at 95% confidence level to determine if the chloride level from the top of the lake is different from that at the bottom
b (15 pts.) Now use the paired t-test to determine whether there is a significant difference between the top and bottom values at the 95% confidence level
Trang 2Analytical chemistry
Semester II, 2020-221
2
c (10 pts.) Why is a different conclusion drawn from using the paired t-test and the normal t-test for differences in means?