# Graded Calculations for Unit 9 Please see Assignments for information on how to

Graded Calculations for Unit 9 Please see Assignments for information on how to prepare and submit Graded Calculations. 1. Consider the reaction: 2NBr3(g) N2(g) + 3Br2(g) At equilibrium and at a particular temperature this system is analyzed and the following concentrations are found: [NBr3] = 2.07 x 10-3 M; [N2] = 4.11 x 10-2 M; [Br2] = 1.06 x 10-3 M. Calculate the value of K for the reaction at this temperature. 2. The equilibrium constant for the reaction H2(g) + F2(g) 2HF(g) has the value 2.1 x 103 at a particular temperature. When the system is analyzed at equilibrium at this temperature, the concentrations of both H2 and F2 are found to be 0.0021 M. What is the concentration of HF in the equilibrium system under these conditions? 3. The solubility product, Ksp, of CdCO3 is 5.2 x 10-12 at 25oC. Calculate the solubility of this salt in mol/L. 4. Copper (II) chromate, CuCrO4, dissolves in water to give a solution that is 1.1 x 10-5 g/L at 23oC. Calculate Ksp for CuCrO4 at this temperature. 5. Approximately 0.14 g of nickel(II) hydroxide, Ni(OH)2(s), dissolves per liter of water at 20oC. Calculate Ksp for Ni(OH)2(s) at this temperature. 6. The solubility product, Ksp, of iron(III) hydroxide is 4 x 10 -38 at 25oC. Calculate the solubility of Fe(OH)3 in mol/L. Hint: Q3 and Q4 above and the examples given in section 17.9 of your text involve solubility calculations where the solid dissolves to produce two ions in a 1:1 molar ratio. Q5 and Q 6 above are also solubility calculations but, in these cases, the solid dissolves to form ions in a 1:2 and 1:3 ratio, respectively. This complicates the question. Make sure that you write the reaction and the solubility expression correctly before attempting these calculations.