# Chem Test Review Questions (multiple chice) Need help , please!

1. Nov 7, 2007

### onehotthunnie

1) Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid (HCO2H) and 0.230 mol of sodium formate (NaCO2H) in water sufficient to yield 1.00 L of solution. THe Ka of formic acid is 1.77 x 10^-4.

a) 2.30 b) 2.09 c) 10.46 d)3.54 e) 3.95

2) The solubility of lead (II) chloride (PbCl2) is 1.6 x 10^-2 M. What is the Ksp of PbCl2?

a)1.6 x 10^-2 b) 5.0 x 10^-4 c) 1.6 x 10^-5 d) 4.1 x 10^-6 e) 3.1 x 10^-7

3) What is the molar solubility of barium fluoride (BaF2) in water? The solubility-product constant for BaF2 is 1.7 x 10^ -6 at 25 degrees celcius.

a) 6.5 x 10^-4 b) 5.7 x 10^-7 c) 7.5 x 10^-3 d) 1.2 x 10^-2 e) 1.8 x 10^-3

4) What is the solubility (in M) of PbCl2 in a 0.15 M solution of HCl? The Ksp of PbCl2 is 1.6 x 10^-5.

a) 1.6 x 10^-5 b) 1.1 x 10^-4 c) 1.8 x 10^-4 d) 7.1 x 10^-4 e)2.0 x 10^-3

5) A 7.0 x 10^-3 M aqueous solution of Ca(OH)2 at 25.0 degrees celsius has a pH of____a) 1.4 x 10 ^-2 b) 7.1 x 10^-13 c) 1.85 d) 12.15 e) 11.85

6) The pH of an aqueous solution at 25.0 degrees celsius is 10.66. What is the molarity of H+ in this solution?

a) 4.6 x 10^10 b) 4.6 x 10^4 c) 1.1 x 10^-13 d) 2.2 x 10^-11 e) 3.3

2. Nov 7, 2007

### mjsd

do u have any ideas on these questions at all?
what exactly can't you do or understand?
by the way, I have never seen or done these before and so I don't have the answers in front of me.

3. Nov 7, 2007

### onehotthunnie

Out of the 42 questions these are the ones I have NO idea what to do. or maybe my brain is tired...

4. Nov 7, 2007

### Gokul43201

Staff Emeritus
The forum guidelines (see rules on top navigation bar) require that we help only after the OP has posted his or her work on the problems. Please show us whatever thoughts/ideas come to you for tackling each question.

Also, henceforth, use the homework & coursework subforum located near the top of the main page.

5. Nov 8, 2007

### symbolipoint

Some of those appear to be very plain equilibria exercise problems. You would need to have studied equilibrium of insoluble inorganic salts, and equilibrium of weak acids and bases. If you have not studied those concepts then having not studied them is the reason that you do not know what to do.
(and now we should again agree with post #4).