Chapter 15 16 Worksheet
Chapter 15/16 Worksheet
Problem (1996 #2)
1)
HOCl <--> OCl- + H+
Hypochlorous acid, HOCl, is a weak acid commonly used as a bleaching agent. The acid-dissociation constant, Ka for the reaction represented above is 3.2 x 10-8.
(a) Calculate the [H+] of a 0.14-molar solution of HOCl. (2 points)
(b) Write the correctly balanced net ionic equation for the reaction that occurs when NaOCl is dissolved in water and calculate the numerical value of the equilibrium constant for the reaction. (2 points)
(c) Calculate the pH of a solution made by combining 40.0 milliliters of 0.14-molar HOCl and 10.0 milliliter of 0.56-molar NaOH. (2 points)
(d) How many millimoles of solid NaOH must be added to 50.0 milliliters of 0.20 - molar HOCl to obtain a buffer solution that has a pH of 7.49? Assume that the addition of the solid NaOH results in a negligible change in volume. (2 points)
(e) Household bleach is made by dissolving chlorine gas in water, as represented below.
Cl2 (g) + H2O --> H+ + Cl- + HOCl (aq)
Calculate the pH of such a solution if the concentration of HOCl in the solution is
0.065 molar. (1 point)
Problem (1994 #1)
2)
MgF2(s) <--> Mg2+(aq) + 2 F-(aq)
In a saturated solution of MgF2 at 18oC, the concentration of Mg2+ is 1.21 x 10-3 molar. The equilibrium is represented by the equation above.
(a) Write the expression for the solubility-product constant, Ksp, and calculate its value at 18oC. (2 points)
(b) Calculate the equilibrium concentration of Mg2+ in 1.000 liter of saturated MgF2 solution at 18oC to which 0.100 mole of solid KF has been added. The KF dissolves completely. Assume the volume change is negligible. (2 points)
Problem (1996 #2)
1)
HOCl <--> OCl- + H+
Hypochlorous acid, HOCl, is a weak acid commonly used as a bleaching agent. The acid-dissociation constant, Ka for the reaction represented above is 3.2 x 10-8.
(a) Calculate the [H+] of a 0.14-molar solution of HOCl. (2 points)
(b) Write the correctly balanced net ionic equation for the reaction that occurs when NaOCl is dissolved in water and calculate the numerical value of the equilibrium constant for the reaction. (2 points)
(c) Calculate the pH of a solution made by combining 40.0 milliliters of 0.14-molar HOCl and 10.0 milliliter of 0.56-molar NaOH. (2 points)
(d) How many millimoles of solid NaOH must be added to 50.0 milliliters of 0.20 - molar HOCl to obtain a buffer solution that has a pH of 7.49? Assume that the addition of the solid NaOH results in a negligible change in volume. (2 points)
(e) Household bleach is made by dissolving chlorine gas in water, as represented below.
Cl2 (g) + H2O --> H+ + Cl- + HOCl (aq)
Calculate the pH of such a solution if the concentration of HOCl in the solution is
0.065 molar. (1 point)
Problem (1994 #1)
2)
MgF2(s) <--> Mg2+(aq) + 2 F-(aq)
In a saturated solution of MgF2 at 18oC, the concentration of Mg2+ is 1.21 x 10-3 molar. The equilibrium is represented by the equation above.
(a) Write the expression for the solubility-product constant, Ksp, and calculate its value at 18oC. (2 points)
(b) Calculate the equilibrium concentration of Mg2+ in 1.000 liter of saturated MgF2 solution at 18oC to which 0.100 mole of solid KF has been added. The KF dissolves completely. Assume the volume change is negligible. (2 points)