Question 1

The concentration of iodine in sea water is 60. parts per billion by mass. If one assumes that the iodine exists in the form of iodide anions, what is the molarity of iodide in sea water? (The density of sea water is 1.025 g/mL.)

Accepted Answer

To find the molarity, convert parts per billion (ppb) to grams per liter using the density of sea water, then divide by the molar mass of iodide (I⁻, approximately 127 g/mol). 60 ppb is 60 mg per 1000 kg of water, which is 60 mg per 1000 L (since 1 kg of water is approximately 1 L). Convert 60 mg to grams (0.060 g), then divide by the molar mass to find moles, and divide by the volume in liters to find molarity: (0.060 g / 127 g/mol) / 1 L = 4.8 × 10⁻⁷ M.

Question 2

Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr₂ in 375.0 g of water.

Accepted Answer

The answer of Cadmium bromide is used in photography and...

Question 3

What is the molality of a solution prepared by dissolving 86.9 g of diethyl ether, C₄H₁₀O, in 425 g of benzene, C₆H₆?

Accepted Answer

The answer of What is the molality of a solution...

Question 4

Children under the age of 6 with more than 0.10 ppm of lead in their blood can suffer a reduction in I.Q. or have behavior problems. What is the molality of a solution which contains 0.10 ppm of lead?

Accepted Answer

The molality is calculated by converting ppm to molality using the formula: molality = (ppm / molar mass) / (density of solvent in kg/L). For lead, with a molar mass of 207.2 g/mol, the calculation gives approximately 4.8 × 10⁻⁷ m.

Question 5

Sodium hydroxide is a common ingredient in drain cleaners such as Drano. The mole fraction of sodium hydroxide in a saturated aqueous solution is 0.310. What is the molality of the solution?

Accepted Answer

The mole fraction of NaOH is 0.310, meaning 0.310 moles of NaOH per 1 mole of solution. The remaining 0.690 moles are water. Molality (m) is moles of solute per kg of solvent. Since 0.690 moles of water is approximately 0.690 kg (assuming 1 mole of water = 18 g), the molality is 0.310 moles NaOH / 0.690 kg water = 0.449 m. However, the closest answer choice is D) 12.4 m, which suggests a calculation error or assumption in the problem setup.

Question 6

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the mole fraction of ethanol in this solution?

Accepted Answer

To find the mole fraction of ethanol, we need to first find the moles of each component in the solution.

Moles of ethanol = mass of ethanol / molar mass of ethanol
= 553 g / 46.07 g/mol = 12.00 mol

Moles of water = mass of water / molar mass of water
= 335 g / 18.02 g/mol = 18.59 mol

The total number of moles in the solution is:

12.00 mol + 18.59 mol = 30.59 mol

The mole fraction of ethanol is then:

12.00 mol / 30.59 mol = 0.392

Question 7

Procaine hydrochloride (ℳ = 272.77 g/mol) is used as a local anesthetic. Calculate the molarity of a 4.666 m solution which has a density of 1.1066 g/mL.

Accepted Answer

The correct answer is A because the molarity of a solution is calculated by dividing the moles of solute by the volume of the solution in liters. The moles of solute can be calculated by dividing the mass of the solute by its molar mass. The volume of the solution can be calculated by dividing the mass of the solution by its density. In this case, the mass of the solute is 4.666 g, the molar mass of the solute is 272.77 g/mol, the mass of the solution is 1.1066 g/mL, and the density of the solution is 1.1066 g/mL. Therefore, the molarity of the solution is 2.272 M.

Question 8

The chemist, Anna Lytic, must prepare 1.00 kg of 15.0% (w/w) acetic acid using a stock solution which is 36.0% (w/w) acetic acid (d = 1.045 g/mL). Which of the following combinations will give her the solution she wants?

Accepted Answer

To prepare 1.00 kg of a 15.0% (w/w) solution, 150 g of acetic acid is needed (15% of 1000 g). Option B correctly uses mass (g) for both acetic acid and water, ensuring the final mixture's mass is 1000 g, with 417 g of 36% acetic acid solution providing the required 150 g of acetic acid (since 36% of 417 g is approximately 150 g).

Question 9

Aqueous ammonia is commercially available in a solution that is 28% (w/w) ammonia. What is the mole fraction of ammonia in such a solution?

Accepted Answer

The answer of Aqueous ammonia is commercially available in a...

Question 10

The mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. Calculate the molarity of the solution.

Accepted Answer

Mole fraction of solute = moles of solute / total moles of solution
Given mole fraction of KNO3 = 0.0194
Let's assume we have 1 L of solution, then the moles of KNO3 present in it= 0.0194 * 1000 = 19.4 moles
To calculate molarity, we need to find the volume of solution in liters, which contains 19.4 moles of KNO3.
Now, let's calculate the mass of the solution containing 1L of solution (1000mL). Mass = volume * density = 1000 * 1.0627 = 1062.7 g
To find the volume of such solution containing 19.4 moles of KNO3, we need to use its molar mass (101.1 g/mol).
Mass of KNO3 = moles of KNO3 * molar mass of KNO3 = 19.4 * 101.1 = 1960.34 g
Now, we can find the volume of solution in liters which contains 19.4 moles of KNO3 by dividing its mass by density.
Volume (in liters) = Mass / Density = 1960.34 / 1.0627 = 1842.26 mL = 1.8422 L
Finally, molarity = moles / volume = 19.4 / 1.8422 = 10.536 M ≈ 1.05 M (rounded to 3 significant figures)

Question 11

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the molality of the ethanol in this solution?

Accepted Answer

The answer of A solution of ethanol (C₂H₆O) in water...

Question 12

Colligative properties depend on

Accepted Answer

Colligative properties are properties of a solution that depend solely on the number of solute particles dissolved in the solvent, not on the chemical nature of the solute. Therefore, the number of particles dissolved is the only relevant factor.

Question 13

Isoamyl salicylate (ℳ = 208.25 g/mol) has a pleasant aroma and is used in perfumes and soaps. Which of the following combinations gives a 0.75 m solution of isoamyl salicylate in ethyl alcohol (d = 0.7893 g/mL)?

Accepted Answer

The correct answer is A because 117.2 g of isoamyl salicylate in 950.0 mL of ethyl alcohol gives a 0.75 m solution.

Question 14

The solubility of the oxidizing agent potassium permanganate is 7.1 g per 100.0 g of water at 25°C. What is the mole fraction of potassium permanganate in this solution?

Accepted Answer

The mole fraction of potassium permanganate is calculated by dividing the moles of potassium permanganate by the total moles of solute and solvent. The moles of potassium permanganate are calculated by dividing the mass of potassium permanganate by its molar mass. The moles of water are calculated by dividing the mass of water by its molar mass. The total moles of solute and solvent are the sum of the moles of potassium permanganate and the moles of water. The mole fraction of potassium permanganate is then calculated by dividing the moles of potassium permanganate by the total moles of solute and solvent.

Question 15

Calcium nitrite is used as a corrosion inhibitor in lubricants. What is the molality of a solution prepared by dissolving 18.5 g of calcium nitrite in 83.5 g of distilled water?

Accepted Answer

The answer of Calcium nitrite is used as a corrosion...

Question 16

Raoult's Law relates the vapor pressure of the solvent above the solution to its mole fraction in the solution. Which of the following is an accurate statement?

Accepted Answer

Raoult's Law works best when applied to dilute solutions, where the intermolecular forces between solute and solvent are weak and the solute does not significantly disrupt the solvent-solvent bonding. In concentrated solutions, the interactions between the solute and solvent become more important and can cause deviations from Raoult's Law. Raoult's Law applies to ideal solutions, but deviations occur with non-ideal solutions.

Question 17

What is the mole fraction of Ne in a mixture containing 10.1 g of Ne, 79.9 g of Ar, and 83.8 g of Kr?

Accepted Answer

To find the mole fraction, first calculate the moles of each gas: Ne (10.1 g / 20.18 g/mol), Ar (79.9 g / 39.95 g/mol), Kr (83.8 g / 83.80 g/mol). Then, find the total moles and divide the moles of Ne by the total moles. The mole fraction of Ne is approximately 0.14.

Question 18

A 2.0% (w/v) solution of sodium hydrogen citrate, Na₂C₆H₆O₇, which also contains 2.5% (w/v) of dextrose, C₆H₁₂O₆, is used as an anticoagulant for blood which is to be used for transfusions. What is the molarity of the sodium hydrogen citrate in the solution?

Accepted Answer

To find the molarity, we need to calculate the moles of sodium hydrogen citrate in 1 liter of solution. A 2.0% (w/v) solution means 2.0 grams of sodium hydrogen citrate per 100 mL of solution. Therefore, in 1 liter (1000 mL), there are 20 grams of sodium hydrogen citrate. The molar mass of Na₂C₆H₆O₇ is approximately 236.1 g/mol. Moles = mass/molar mass = 20 g / 236.1 g/mol ≈ 0.085 mol. Thus, the molarity is approximately 0.085 M.

Question 19

A 0.89% (w/v) sodium chloride solution is referred to as physiological saline solution because it has the same concentration of salts as human blood. What is the molarity of a physiological saline solution?

Accepted Answer

To calculate the molarity, we need to first find the moles of sodium chloride present in one liter of 0.89% (w/v) solution.

0.89% (w/v) = 0.89 g/100 mL
Since the density of water is 1 g/mL, we can convert this to mass per liter (1000 mL):
0.89 g/100 mL x 10 = 8.9 g/L

The molecular weight of NaCl is 58.44 g/mol.
So, the number of moles of NaCl in one liter of solution is:
8.9 g/L ÷ 58.44 g/mol = 0.1522 mol/L

Therefore, the molarity of the solution is 0.1522 M, which is closest to answer choice C (0.15 M).

Question 20

Copper(II) bromide is used as a wood preservative. What mass of CuBr₂ is needed to prepare 750.0 mL of a 1.25 M solution?

Accepted Answer

To find the mass of CuBr2 needed to prepare a 750.0 mL (0.750 L) solution of 1.25 M concentration, use the formula: mass = molarity (M) × volume (L) × molar mass (g/mol). The molar mass of CuBr2 is approximately 223.36 g/mol. So, mass = 1.25 mol/L × 0.750 L × 223.36 g/mol = 209 g.

Quiz 13: The Properties of Mixtures: Solutions and Colloids

The concentration of iodine in sea water is 60. parts per billion by mass. If one assumes that the iodine exists in the form of iodide anions, what is the molarity of iodide in sea water? (The density of sea water is 1.025 g/mL.)

Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr₂ in 375.0 g of water.

What is the molality of a solution prepared by dissolving 86.9 g of diethyl ether, C₄H₁₀O, in 425 g of benzene, C₆H₆?

Children under the age of 6 with more than 0.10 ppm of lead in their blood can suffer a reduction in I.Q. or have behavior problems. What is the molality of a solution which contains 0.10 ppm of lead?

Sodium hydroxide is a common ingredient in drain cleaners such as Drano. The mole fraction of sodium hydroxide in a saturated aqueous solution is 0.310. What is the molality of the solution?

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the mole fraction of ethanol in this solution?

Procaine hydrochloride (ℳ = 272.77 g/mol) is used as a local anesthetic. Calculate the molarity of a 4.666 m solution which has a density of 1.1066 g/mL.

The chemist, Anna Lytic, must prepare 1.00 kg of 15.0% (w/w) acetic acid using a stock solution which is 36.0% (w/w) acetic acid (d = 1.045 g/mL) . Which of the following combinations will give her the solution she wants?

Aqueous ammonia is commercially available in a solution that is 28% (w/w) ammonia. What is the mole fraction of ammonia in such a solution?

The mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. Calculate the molarity of the solution.

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the molality of the ethanol in this solution?

Colligative properties depend on

Isoamyl salicylate (ℳ = 208.25 g/mol) has a pleasant aroma and is used in perfumes and soaps. Which of the following combinations gives a 0.75 m solution of isoamyl salicylate in ethyl alcohol (d = 0.7893 g/mL) ?

The solubility of the oxidizing agent potassium permanganate is 7.1 g per 100.0 g of water at 25°C. What is the mole fraction of potassium permanganate in this solution?

Calcium nitrite is used as a corrosion inhibitor in lubricants. What is the molality of a solution prepared by dissolving 18.5 g of calcium nitrite in 83.5 g of distilled water?

Raoult's Law relates the vapor pressure of the solvent above the solution to its mole fraction in the solution. Which of the following is an accurate statement?

What is the mole fraction of Ne in a mixture containing 10.1 g of Ne, 79.9 g of Ar, and 83.8 g of Kr?

A 2.0% (w/v) solution of sodium hydrogen citrate, Na₂C₆H₆O₇, which also contains 2.5% (w/v) of dextrose, C₆H₁₂O₆, is used as an anticoagulant for blood which is to be used for transfusions. What is the molarity of the sodium hydrogen citrate in the solution?

A 0.89% (w/v) sodium chloride solution is referred to as physiological saline solution because it has the same concentration of salts as human blood. What is the molarity of a physiological saline solution?

Copper(II) bromide is used as a wood preservative. What mass of CuBr₂ is needed to prepare 750.0 mL of a 1.25 M solution?

Quiz 13: The Properties of Mixtures: Solutions and Colloids

The concentration of iodine in sea water is 60. parts per billion by mass. If one assumes that the iodine exists in the form of iodide anions, what is the molarity of iodide in sea water? (The density of sea water is 1.025 g/mL.)

Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr2 in 375.0 g of water.

What is the molality of a solution prepared by dissolving 86.9 g of diethyl ether, C4H10O, in 425 g of benzene, C6H6?

Children under the age of 6 with more than 0.10 ppm of lead in their blood can suffer a reduction in I.Q. or have behavior problems. What is the molality of a solution which contains 0.10 ppm of lead?

Sodium hydroxide is a common ingredient in drain cleaners such as Drano. The mole fraction of sodium hydroxide in a saturated aqueous solution is 0.310. What is the molality of the solution?

A solution of ethanol (C2H6O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the mole fraction of ethanol in this solution?

Procaine hydrochloride (ℳ = 272.77 g/mol) is used as a local anesthetic. Calculate the molarity of a 4.666 m solution which has a density of 1.1066 g/mL.

The chemist, Anna Lytic, must prepare 1.00 kg of 15.0% (w/w) acetic acid using a stock solution which is 36.0% (w/w) acetic acid (d = 1.045 g/mL) . Which of the following combinations will give her the solution she wants?

Aqueous ammonia is commercially available in a solution that is 28% (w/w) ammonia. What is the mole fraction of ammonia in such a solution?

The mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. Calculate the molarity of the solution.

A solution of ethanol (C2H6O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the molality of the ethanol in this solution?

Colligative properties depend on

Isoamyl salicylate (ℳ = 208.25 g/mol) has a pleasant aroma and is used in perfumes and soaps. Which of the following combinations gives a 0.75 m solution of isoamyl salicylate in ethyl alcohol (d = 0.7893 g/mL) ?

The solubility of the oxidizing agent potassium permanganate is 7.1 g per 100.0 g of water at 25°C. What is the mole fraction of potassium permanganate in this solution?

Calcium nitrite is used as a corrosion inhibitor in lubricants. What is the molality of a solution prepared by dissolving 18.5 g of calcium nitrite in 83.5 g of distilled water?

Raoult's Law relates the vapor pressure of the solvent above the solution to its mole fraction in the solution. Which of the following is an accurate statement?

What is the mole fraction of Ne in a mixture containing 10.1 g of Ne, 79.9 g of Ar, and 83.8 g of Kr?

A 2.0% (w/v) solution of sodium hydrogen citrate, Na2C6H6O7, which also contains 2.5% (w/v) of dextrose, C6H12O6, is used as an anticoagulant for blood which is to be used for transfusions. What is the molarity of the sodium hydrogen citrate in the solution?

A 0.89% (w/v) sodium chloride solution is referred to as physiological saline solution because it has the same concentration of salts as human blood. What is the molarity of a physiological saline solution?

Copper(II) bromide is used as a wood preservative. What mass of CuBr2 is needed to prepare 750.0 mL of a 1.25 M solution?

Cadmium bromide is used in photography and lithography. Calculate the molality of a solution prepared by dissolving 45.38 g of CdBr₂ in 375.0 g of water.

What is the molality of a solution prepared by dissolving 86.9 g of diethyl ether, C₄H₁₀O, in 425 g of benzene, C₆H₆?

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the mole fraction of ethanol in this solution?

A solution of ethanol (C₂H₆O) in water is sometimes used as a disinfectant. 1.00 L of this solution contains 553 g of ethanol and 335 g of water. What is the molality of the ethanol in this solution?

A 2.0% (w/v) solution of sodium hydrogen citrate, Na₂C₆H₆O₇, which also contains 2.5% (w/v) of dextrose, C₆H₁₂O₆, is used as an anticoagulant for blood which is to be used for transfusions. What is the molarity of the sodium hydrogen citrate in the solution?

Copper(II) bromide is used as a wood preservative. What mass of CuBr₂ is needed to prepare 750.0 mL of a 1.25 M solution?