CHM 1046 Quiz 4 1. A precipitate will form when a solution containing a cation a

Question

CHM 1046 Quiz 4 1. A precipitate will form when a solution containing a cation and a solution containing an anion aze sixed if the exceeda the value of the Answer 2. The pt ot a saturated solution of Mg (0)2 vhose Ksp is 7.1-10 12, Ansver 3. The solubility product for chomium(I) fluoride is Ksp -6.6x10 11. Using this information, what is the molar solubility of chromiun(IID luoride? Answer 4. Calculate the concentration of chloride ions in a saturated lead (II) chloride solution. The Kap 2.4 x 104 tor lead(II) chloride. Answer: 5. A student mixes 50.00 mi. of 0.500 M NaCl with 75.00 nl of 0.200 M AgNO3. Will a precipitate form? What is the identity of the precipitate? Consult Table 17.1 in your text. Answer: 6. What is the molar solubility of Ca (08)2 in a 0.300 M NaOH solution? The Kap of Ca (OH)2is 6.5 x 10. Ansver:

Explanation / Answer

1. A precipitate from a solution is formed when the value of Qsp exceeds the value of Ksp.

2. Ksp Mg(OH)2 = [Mg2+][OH-]^2 = 7.1 x 10^-12

let x amount of salt is in solution, than x amount of Mg2+ and 2x amount of OH- would be in solution

7.1 x 10^-12 = (x)(2x)^2

x = 1.21 x 10^-4 M

So,

[OH-] = 2 x 1.21 x 10^-4 = 2.42 x 10^-4 M

[H+] = 1 x 10^-14/2.42 x 10^-4 = 4.13 x 10^-11 M

pH = -log[H+] = -log(4.13 x 10^-4) = 10.38

4. let x amount of PbCl2 is in solution

than x amount of Pb2+ and 2x amount of Cl- would be in solution

Ksp = [Pb2+][Cl-]^2

2.4 x 10^-4 = (x)(2x)^2

x = 0.039 M

concentration [Cl-] = 2 x 0.039 = 0.08 M

5. Qsp AgCl = [Ag+][Cl-]

                    = (0.5 M x 50 ml/125 ml)(0.2 M x 75 ml/125 ml)

                    = 0.024

Ksp of AgCl = 1.8 x 10^-10

So,

Qsp > Ksp, therefore solution is saturated. Precipitate would form.

6. Ksp for Ca(OH)2 = [Ca2+][OH-]^2

with,

[OH-] = 0.3 M

molar solubility = [Ca2+] = Ksp/[OH-]^2

                                        = 6.5 x 10^-6/(0.3)^2

                                        = 7.22 x 10^-5 M

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.