7/22/2019 Analytical Chem Practice

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Introduction to Analytical Chemistry, October 22, 2010 (Review for Exam by Dr. Roto)

1. You have available 12.0 M HCl (concentrated HCl) and wish to prepare 0.500 L of 0.750

M HCl for use in an experiment. How do you prepare such a solution?2. A water sample from a well had a calcium level of 193 ppm. What would this

concentration be if you expressed in as molarity?

3. Convert of molarity to ppm solution of 0.02500 M K2SO4

4. What is the concentration, on a %(w:v) basis, of vanadium in a solution that contains 281.5 mg/L

of vanadium?

5. How many millileters of 0.100M KI are needed to react with 40.00 ml of 0.0400 M

Hg2(NO3) if the reaction is: Hg2 + + 2I- Hg2I2(s)?

6. Calculate the pH of the following solutions:a. 0.045M HCl

b. 0.00000045M HNO3

c. 0.00045 M Ca(OH)2

7. I am going to mix 50 ml of a solution that is saturated in PbI2 with 10 ml of a 0.50 M KIsolution. What is the final concentration of I- and Pb+2in this solution? (Show all

calculations. If you had to use the solver function on your calculator, state the equation

that you used. If you make any assumptions, state the assumptions that you used and

prove they are good.)

8. The small and taste of fish arises from amine compounds. Suggest a reason why adding

lemon juice (which is acidic) reduces the fishy smell. Suggest another common

household product you use to reduce the fishy smell if you didnt have lemon juice.

9. I have an acid solution that has a formal concentration of 0.0010 M; at this concentrationthe acid is 7.5% dissociated. What is the pH of the solution, and what is the pKa of the

acid?

10. Butanoic acid (CH3CH2CH2COOH) is a weak acid with a pKa of 4.818. What is the pH of

a 0.02M solution of sodium butanoate (CH3CH2CH2COONa)?

11. I want to make a buffer that will keep the pH of a solution at 11.0. If I start by dissolving15 g of piperidine in 1L of water, how many mls of either 1.0 M HCl, or 1.0 M NaOH

will I have to add to this solution to make my buffer? From the above structure you

should come up with the formula C5H11N for piperidine, and get a molar mass of 85.148 g

N

Piperidine, pKa=11.125.

(Please find Ksp, atomic mass, etc in a text book)