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Problem 110a
(a) Write the net ionic equation for the reaction that occurs when a solution of hydrochloric acid (HCl) is mixed with a solution of sodium formate 1NaCHO22.
Problem 111a
(a) A 0.1044-g sample of an unknown monoprotic acid requires 22.10 mL of 0.0500 M NaOH to reach the end point. What is the molar mass of the unknown?
Problem 111b
(b) As the acid is titrated, the pH of the solution after the addition of 11.05 mL of the base is 4.89. What is the Ka for the acid?
- A sample of 7.5 L of NH3 gas at 22 _x001F_C and 735 torr is bubbled into a 0.50-L solution of 0.40 M HCl. Assuming that all the NH3 dissolves and that the volume of the solution remains 0.50 L, calculate the pH of the resulting solution.
Problem 112
Problem 114
What is the pH at 25 C of water saturated with CO2 at a partial pressure of 1.10 atm? The Henry's law constant for CO2 at 25 C is 3.1 * 10-2 mol>L@atm.
- Excess Ca(OH)₂ is shaken with water to produce a saturated solution. The solution is filtered, and a 50.00-mL sample is titrated with HCl, requiring 11.23 mL of 0.0983 M HCl to reach the endpoint. Calculate Ksp for Ca(OH)₂. Compare your result with that in Appendix D. Suggest a reason for any differences you find between your value and the one in Appendix D.
Problem 115
Problem 116
The osmotic pressure of a saturated solution of strontium sulfate at 25 C is 21 torr. What is the solubility product of this salt at 25 C?
Problem 117b,c
A concentration of 10–100 parts per billion (by mass) of Ag+ is an effective disinfectant in swimming pools. However, if the concentration exceeds this range, the Ag+ can cause adverse health effects. One way to maintain an appropriate concentration of Ag+ is to add a slightly soluble salt to the pool. Using Ksp values from Appendix D, calculate the equilibrium concentration of Ag+ in parts per billion that would exist in equilibrium with (b) AgBr (c) AgI.
Problem 118
Fluoridation of drinking water is employed in many places to aid in the prevention of tooth decay. Typically. the Fion concentration is adjusted to about 1 ppm. Some water supplies are also 'hard'; that is, they contain certain cations such as Ca2 + that interfere with the action of soap. Consider a case where the concentration of Ca2 + is 8 ppm. Could a precipitate of CaF2 form under these conditions? (Make any necessary approximations.)
Problem 119a
Baking soda (sodium bicarbonate, NaHCO3) reacts with acids in foods to form carbonic acid (H2CO3), which in turn decomposes to water and carbon dioxide gas. In a cake batter, the CO2(g) forms bubbles and causes the cake to rise. (a) A rule of thumb in baking is that 1/2 teaspoon of baking soda is neutralized by one cup of sour milk. The acid component in sour milk is lactic acid, CH3CH(OH)COOH. Write the chemical equation for this neutralization reaction.
Problem 119b
Baking soda (sodium bicarbonate, NaHCO3) reacts with acids in foods to form carbonic acid (H2CO3), which in turn decomposes to water and carbon dioxide gas. In a cake batter, the CO2(g) forms bubbles and causes the cake to rise. (b) The density of baking soda is 2.16 g/cm3. Calculate the concentration of lactic acid in one cup of sour milk (assuming the rule of thumb applies), in units of mol/L. (One cup = 236.6 mL = 48 teaspoons).
Problem 119c
Baking soda (sodium bicarbonate, NaHCO3) reacts with acids in foods to form carbonic acid (H2CO3), which in turn decomposes to water and carbon dioxide gas. In a cake batter, the CO2(g) forms bubbles and causes the cake to rise. (c) If 1/2 teaspoon of baking soda is indeed completely neutralized by the lactic acid in sour milk, calculate the volume of carbon dioxide gas that would be produced at 1 atm pressure, in an oven set to 350 F.
Problem 120
In nonaqueous solvents, it is possible to react HF to create H2F+. Which of these statements follows from this observation? (a) HF can act like a strong acid in nonaqueous solvents, (b) HF can act like a base in nonaqueous solvents, (c) HF is thermodynamically unstable, (d) There is an acid in the nonaqueous medium that is a stronger acid than HF.