Calculate the solubility of CaF2 in g/L (Ksp = 4.0 x 10-8). 2. What is the pH of a solution containing a hydrogen ion concentration of 3.0x10-4M? 3. What is the oxidizing agent and reducing agent in the following reaction: Zn(s) + Cl2(g) → ZnCl2(s) 4. Assign the oxidation numbers of the atoms in the following compounds. (a) Al2O3 (b) XeF4 (c) K2Cr2O7

Explanation:

1. Solubility of CaF_2

(a) Molar solubility

CaF₂ ⇌ Ca²⁺ + 2F⁻

(b) Mass solubility

2. pH

pH = -log [H⁺] = -log(3.0 × 10⁻⁴) = 3.52

3. Oxidizing and reducing agents

Zn + Cl₂ ⟶ ZnCl₂

The oxidation number of Cl has decreased from 0 to -1.

Cl has been reduced, so Cl is the oxidizing agent.

4. Oxidation numbers

(a) Al₂O₃

1O = -2; 3O = -6; 2Al  = +6; 1Al = +3

(b) XeF₄

1F = -1; 4F = -4; 1 Xe = +4

(c) K₂Cr₂O₇

1K = +1; 2K = +2; 1O = -2; 7O = -14

+2 - 14 = -12

2Cr = + 12; 1 Cr = +6

hurricanes form when warm, moist air from the ocean surface quickly rises into the atmosphere and forms storm clouds and rain. when the clouds are formed, heat is released which warms the cool air in the upper regions of the atmosphere so that the cycle can continue. which two phases of the water cycle are repeated in this process?