Fall2008 Exam 3 Chapter 16 and 18

Fall2008 Exam 3 Chapter 16 and 18 - Be sure to show your...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Be sure to show your work and give the proper units in the answer. Any problems that have answers without supporting work will only receive half credit. You can use the back side of these sheets if additional space is required (make a note in the problem if you do this). Section I. (30pts total) Be sure to read each question completely before you begin the answer it. In general, this section contains simple concept based questions that have few calculations. 1.1 (2pts) Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is the best for making a buffer solution with a pH of 8.5? A. CH 3 COO 2 Na/CH 3 COOH (K a = 1.8 × 10 -5 ) B. NaCl/HCl C. NaOCl/HOCl (K a = 3.2 × 10 -8 ) D. NaNO 2 /HNO 2 (K a = 4.5 × 10 -4 ) E. NH 3 /NH 4 Cl (K a = 5.6 × 10 -10 ) 1.2 (2pts) Solid sodium iodide is slowly added to a solution that is 0.0050 M Pb 2+ and 0.0050 M Ag + . (K sp (PbI 2 ) = 1.4 × 10 -8 ; K sp (AgI) = 8.3 × 10 -17 ) What compound will precipitate first? _______________ AgI Å 1.3 (3pts) At 25 ° C, the base ionization constant for NH 3 is 1.8 × 10 -5 . Determine the pH of a solution prepared by adding 0.0500 mol of solid ammonium chloride to 100. mL of 0.150 M ammonia. 8.73 Å Answer=_______________________________________ 1.4 (4pts) Find the concentration of calcium ions in a solution made by adding 3.50 g of calcium fluoride to 750. mL of 0.125 M NaF. [For CaF
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

Fall2008 Exam 3 Chapter 16 and 18 - Be sure to show your...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online