Brown - Chemistry: The Central Science 15th Edition

Ch.4 - Reactions in Aqueous Solution

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Brown 15th Edition

Ch.4 - Reactions in Aqueous Solution

Problem 82c
(c) If 55.8 mL of a BaCl₂ solution is needed to precipitate all the sulfate ion in a 752-mg sample of Na₂SO₄, what is the molarity of the BaCl₂ solution?
Problem 83
Some sulfuric acid is spilled on a lab bench. You can neutralize the acid by sprinkling sodium bicarbonate on it and then mopping up the resulting solution. The sodium bicarbonate reacts with sulfuric acid according to: 2 NaHCO3(s) + H2SO4(aq) → Na2SO4(aq) + 2 H2O(l) + 2 CO2(g). Sodium bicarbonate is added until the fizzing due to the formation of CO2(g) stops. If 27 mL of 6.0 M H2SO4 was spilled, what is the minimum mass of NaHCO3 that must be added to the spill to neutralize the acid?
Problem 84
The distinctive odor of vinegar is due to acetic acid, CH3COOH, which reacts with sodium hydroxide according to: CH3COOH1aq2 + NaOH1aq2¡ H2O1l2 + NaCH3COO1aq2 If 3.45 mL of vinegar needs 42.5 mL of 0.115 M NaOH to reach the equivalence point in a titration, how many grams of acetic acid are in a 1.00-qt sample of this vinegar?
Problem 85a
A 4.36-g sample of an unknown alkali metal hydroxide is dissolved in 100.0 mL of water. An acid–base indicator is added, and the resulting solution is titrated with 2.50 M HCl(aq) solution. The indicator changes color, signaling that the equivalence point has been reached, after 17.0 mL of the hydrochloric acid solution has been added. (a) What is the molar mass of the metal hydroxide?
Problem 85b
A 4.36-g sample of an unknown alkali metal hydroxide is dissolved in 100.0 mL of water. An acid–base indicator is added, and the resulting solution is titrated with 2.50 M HCl(aq) solution. The indicator changes color, signaling that the equivalence point has been reached, after 17.0 mL of the hydrochloric acid solution has been added. (b) What is the identity of the alkali metal cation: Li⁺, Na⁺, K⁺, Rb⁺, or Cs⁺?
Problem 86
An 8.65-g sample of an unknown group 2 metal hydroxide is dissolved in 85.0 mL of water. An acid–base indicator is added and the resulting solution is titrated with 2.50 M HCl(aq) solution. The indicator changes color, signaling that the equivalence point has been reached, after 56.9 mL of the hydrochloric acid solution has been added. (a) What is the molar mass of the metal hydroxide? (b) What is the identity of the metal cation: Ca²⁺, Sr²⁺, or Ba²⁺?
Problem 87a
A solution of 100.0 mL of 0.200 M KOH is mixed with a solution of 200.0 mL of 0.150 M NiSO₄. (a) Write the balanced chemical equation for the reaction that occurs.
Problem 87b
A solution of 100.0 mL of 0.200 M KOH is mixed with a solution of 200.0 mL of 0.150 M NiSO_4.(b) What precipitate forms?
Problem 87e
A solution of 100.0 mL of 0.200 M KOH is mixed with a solution of 200.0 mL of 0.150 M NiSO₄. (e) What is the concentration of each ion that remains in solution?
Problem 88b
A solution is made by mixing 15.0 g of Sr⁡(OH)2 and 55.0 mL of 0.200 M HNO3. b. Calculate the concentration of each ion remaining in solution.
Problem 88c
A solution is made by mixing 15.0 g of Sr⁡(OH)2 and 55.0 mL of 0.200 M HNO3. c. Is the resulting solution acidic or basic?
Problem 89
A 0.5895-g sample of impure magnesium hydroxide is dissolved in 100.0 mL of 0.2050 M HCl solution. The excess acid then needs 19.85 mL of 0.1020 M NaOH for neutralization. Calculate the percentage by mass of magnesium hydroxide in the sample, assuming that it is the only substance reacting with the HCl solution.
Problem 90
A 1.248-g sample of limestone rock is pulverized and then treated with 30.00 mL of 1.035 M HCl solution. The excess acid then requires 11.56 mL of 1.010 M NaOH for neutralization. Calculate the percentage by mass of calcium carbonate in the rock, assuming that it is the only substance reacting with the HCl solution.
Problem 91b
Uranium hexafluoride, UF6, is processed to produce fuel for nuclear reactors and nuclear weapons. UF6 is made from the reaction of elemental uranium with ClF3, which also produces Cl2 as a by-product. b. Is this a metathesis reaction?
Problem 92b
The accompanying photo shows the reaction between a solution of Cd(NO₃)₂ and one of Na₂S. (b) What ions remain in solution?
Problem 92d
The accompanying photo shows the reaction between a solution of Cd(NO₃)₂ and one of Na₂S. (d) Is this a redox reaction?
Problem 93
Suppose you have a solution that might contain any or all of the following cations: Ni2+, Ag+, Sr2+, and Mn2+. Addition of HCl solution causes a precipitate to form. After filtering off the precipitate, H2SO4 solution is added to the resulting solution and another precipitate forms. This is filtered off, and a solution of NaOH is added to the resulting solution. No precipitate is observed. Which of the four ions listed above must be absent from the original solution?

Problem 94

You choose to investigate some of the solubility guidelines for two ions not listed in Table 4.1, the chromate ion (CrO₄²⁻) and the oxalate ion (C₂O₄²⁻). You are given 0.01 M solutions (A, B, C, D) of four water-soluble salts: When these solutions are mixed, the following observations are made:

(a) Write a net ionic equation for the reaction that occurs in the first experiment. (b) Identify the precipitate formed in the first experiment. (c) Write a net ionic equation for the reaction that occurs in the third experiment. (d) Identify the precipitate formed in the third experiment. (e) Write a net ionic equation for the reaction that occurs in the fourth experiment. (f) Identify the precipitate formed in the fourth experiment. (g) Write a net ionic equation for the reaction that occurs in the fifth experiment. (h) Identify the precipitate formed in the fifth experiment. (i) Write a net ionic equation for the reaction that occurs in the sixth experiment. (j) Identify the precipitate formed in the sixth experiment.

Problem 95

Antacids are often used to relieve pain and promote healing in the treatment of mild ulcers. Write balanced net ionic equations for the reactions between the aqueous HCl in the stomach and each of the following substances used in various antacids: (a) Al(OH)₃(s) (b) Mg(OH)₂(s) (c) MgCO₃(s) (d) NaAl(CO₃)(OH)₂(s) (e) CaCO₃(s).

Problem 96a

The commercial production of nitric acid involves the following chemical reactions:

4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

2 NO(g) + O₂(g) → 2 NO₂(g)

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

(a) Which of these reactions are redox reactions?

Problem 96b

The commercial production of nitric acid involves the following chemical reactions:

4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

2 NO(g) + O₂(g) → 2 NO₂(g)

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

(b) Identify the element undergoing oxidation and the element undergoing reduction.

Problem 96c

The commercial production of nitric acid involves the following chemical reactions:

4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

2 NO(g) + O₂(g) → 2 NO₂(g)

3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g)

(c) How many grams of ammonia must you start with to make 1000.0 L of a 0.150 M aqueous solution of nitric acid? Assume all the reactions give 100% yield.

Problem 97b

Neurotransmitters are molecules that are released by nerve cells to other cells in our bodies, and are needed for muscle motion, thinking, feeling, and memory. Dopamine is a common neurotransmitter in the human brain and is a weak base. Its molecular weight is 153.2 g/mol. b. Experiments with rats show that if rats are dosed with 3.0 mg/kg of cocaine (that is, 3.0 mg cocaine per kg of animal mass), the concentration of dopamine in their brains increases by 0.75 𝜇𝑀 after 60 seconds. Calculate how many molecules of dopamine would be produced in a rat (average brain volume 5.00mm3) after 60 seconds of a 3.0 mg/kg dose of cocaine.

Problem 98a

Hard water contains Ca2+, Mg2+, and Fe2+, which interfere with the action of soap and leave an insoluble coating on the insides of containers and pipes when heated. Water softeners replace these ions with Na+. Keep in mind that charge balance must be maintained. (a) If 1500 L of hard water contains 0.020 M Ca2+ and 0.0040 M Mg2+, how many moles of Na+ are needed to replace these ions?

Problem 98b

Hard water contains Ca2+, Mg2+, and Fe2+, which interfere with the action of soap and leave an insoluble coating on the insides of containers and pipes when heated. Water softeners replace these ions with Na+. Keep in mind that charge balance must be maintained. (b) If the sodium is added to the water softener in the form of NaCl, how many grams of sodium chloride are needed?

Problem 99a

Tartaric acid, H2C4H4O6, has two acidic hydrogens. The acid is often present in wines, and a salt derived from the acid precipitates from solution as the wine ages. A solution containing an unknown concentration of the acid is titrated with NaOH. It requires 24.65 mL of 0.2500 M NaOH solution to titrate both acidic protons in 50.00 mL of the tartaric acid solution. Write a balanced net ionic equation for the neutralization reaction

Problem 99b

Tartaric acid, H2C4H4O6, has two acidic hydrogens. The acid is often present in wines, and a salt derived from the acid precipitates from solution as the wine ages. A solution containing an unknown concentration of the acid is titrated with NaOH. It requires 24.65 mL of 0.2500 M NaOH solution to titrate both acidic protons in 50.00 mL of the tartaric acid solution. Calculate the molarity of the tartaric acid solution.

Problem 100c

If 23.9 mL of the strontium hydroxide solution was needed to neutralize a 37.5 mL aliquot of the nitric acid solution, what is the concentration (molarity) of the acid?

Problem 101

A solid sample of Zn⁡(OH)2 is added to 0.350 L of 0.500 M aqueous HBr. The solution that remains is still acidic. It is then titrated with 0.500 M NaOH solution, and it takes 88.5 mL of the NaOH solution to reach the equivalence point. What mass of Zn⁡(OH)2 was added to the HBr solution?

Problem 102d

Suppose you have 5.00 g of powdered magnesium metal, 1.00 L of 2.00 M potassium nitrate solution, and 1.00 L of 2.00 M silver nitrate solution. d. What is the molarity of the Mg2+ ions in the resulting solution?

Problem 82c

Problem 83

Problem 84

Problem 85a

Problem 85b

Problem 86

Problem 87a

Problem 87b

Problem 87e

Problem 88b

Problem 88c

Problem 89

Problem 90

Problem 91b

Problem 92b

Problem 92d

Problem 93

Problem 94

Problem 95

Problem 96a

Problem 96b

Problem 96c

Problem 97b

Problem 98a

Problem 98b

Problem 99a

Problem 99b

Problem 100c

Problem 101

Problem 102d