Calculate the mean for the following 4 numbers for the concentration of chloride in a sample: 0.1015, 0.0991, 0.1016, and 0.1017.     

In the lab I get the following 4 numbers for the concentration of chloride in a sample:
0.1015, 0.0991, 0.1016, and 0.1017. What is the 95% confidence interval, and the relative
standard deviation for this data set.

Calculate the concentration of chloride ions in a saturated lead(II) chloride (Ksp = 2.4 ? 10-4) solution.

Analysis of an Unknown Chloride

1. A student performed this experiment and obtained the following concentration values: 0.02813 M, 0.02802 M, and 0.02788 M.

a. What is the mean concentration? ____________ M

b. What is the standard deviation of these results? ____________ M

2. A 10.00 mL diluted chloride sample required 13.89 mL of 0.02014 M AgNO3 to reach the Fajans endpoint.

a. How many moles of Cl− ion were present in the sample? (Use Eqs. 2 and 3.) ____________ moles Cl−

b. What was the concentration of chloride in the diluted solution? ____________ M

3. How would the following errors affect the concentration of Cl− obtained in Question 2b? Give your reasoning in each case.

a. The student read the molarity of AgNO3 as 0.02104 M instead of 0.02014 M.

b. The student was past the endpoint of the titration when he took the final buret reading.