Question 1

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Accepted Answer

E

Question 2

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Accepted Answer

Wax is nonpolar, and nonpolar solvents are best for dissolving nonpolar substances. E is a long-chain hydrocarbon, making it nonpolar and similar to wax, thus more capable of dissolving it.

Question 3

Which response lists all the following pairs that are miscible liquids? Pair 1. octane (C₈H₁₈)and water Pair 2. ammonia (NH₃)and water Pair 3. octane (C₈H₁₈)and carbon tetrachloride (CCl₄)

Accepted Answer

Octane and carbon tetrachloride are both nonpolar molecules, so they are miscible with each other. Ammonia and water are both polar molecules, so they are miscible with each other. Octane and water are immiscible because octane is nonpolar and water is polar.

Question 4

Concerning the process of separating of a solid substance into its component units (molecules or ions),

Accepted Answer

The process of separating a solid into its component units requires energy to overcome the forces holding the units together, making it endothermic, and the potential energy increases as the components are separated.

Question 5

Concerning the solvation step of the solution process,

Accepted Answer

The solvation process is exothermic because energy is released when solute particles interact with solvent molecules, leading to a decrease in potential energy.

Question 6

KBr has a lattice energy of -682 kJ/mol and a hydration energy of -657 kJ/mol. Using this information, what is the heat of solution, $\Delta$H_sol, for KBr?Hint: What happens to the crystal lattice when an ionic compound dissolves?

Accepted Answer

The heat of solution is calculated as the sum of the lattice energy and the hydration energy: $\Delta$H_sol = -682 kJ/mol + 657 kJ/mol = +25 kJ/mol.

Question 7

A solution in a beaker has some undissolved solute lying on the bottom of the beaker. If the rate of crystallization exceeds the rate of dissolution of the excess solute, the solution is described as

Accepted Answer

The solution is supersaturated when the rate of crystallization exceeds the rate of dissolution of the excess solute.

Question 8

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of crystallization is equal to the rate of dissolution of the excess solute, the solution is described as

Accepted Answer

A saturated solution is one where the rate of dissolution of the solute is equal to the rate of crystallization, meaning no more solute can dissolve at that temperature and pressure.

Question 9

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of dissolution of the solute exceeds the rate of crystallization, the solution is described as

Accepted Answer

If the rate of dissolution exceeds the rate of crystallization, it means the solution can still dissolve more solute, indicating that it is unsaturated.

Question 10

A solution is sitting undisturbed on a side shelf in the laboratory. A small crystal of the same solute of which the solution is made was gently dropped into the solution. Suddenly, a mass of crystals forms and settles to the bottom of the container. The solution is, or must have been

Accepted Answer

The rapid formation of crystals upon adding a small crystal indicates that the solution was supersaturated, meaning it contained more solute than it could normally hold at that temperature. The added crystal provided a nucleation site for the excess solute to crystallize out.

Question 11

Which of the following will always cause an increase in the solubility of a gas in a solvent in which the gas does not react with the solvent to form a new substance?

Accepted Answer

Decreasing the temperature of the solvent and increasing the pressure of the gas above the solvent both favor the dissolution of gases, according to Henry's Law and the general behavior of gases in solution.

Question 12

The solubility of O₂ in water is approximately 0.00380 g L^-1 when the temperature is 25.0°C and the partial pressure of gaseous oxygen is 760. torr. What will the solubility of oxygen be if the oxygen pressure is adjusted to 1000 torr?

Accepted Answer

According to Henry's law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas. Therefore, if the pressure increases from 760 torr to 1000 torr, the solubility will increase proportionally: (1000/760) * 0.00380 g L^-1 = 0.00500 g L^-1.

Question 13

The solubility of O₂ in water is approximately 0.00380 g L^-1 of water when the temperature is 25.0°C and the partial pressure of gaseous oxygen is 760 torr. The oxygen gas above the water is replaced by air at the same temperature and pressure, in which the mole fraction of oxygen is 0.210. What will the solubility of oxygen in water be under these new conditions?

Accepted Answer

The solubility of a gas in a liquid is directly proportional to its partial pressure above the liquid. The partial pressure of O2 in air is 0.210 × 760 torr. The new solubility is (0.210 × 760/760) × 0.00380 g L⁻¹ = 7.98 × 10⁻⁴ g L⁻¹.

Question 14

A solution is made by mixing 138.2 grams of ethanol, C₂H₆O, (46.069 g mol^-1); 103.6 grams of water (18.015 g mol^-1), and 80.11 grams of methanol, CH₄O, (32.042 g mol^-1). What is the mole fraction of methanol in the mixture?

Accepted Answer

The answer of A solution is made by mixing 138.2...

Question 15

The CO₂ gas sealed inside a carbonated beverage bottle has a pressure of 3.750 atm. At this pressure, the solubility of CO₂ in water is 0.65 g CO₂/100 g H₂O. If the bottle is opened, as the gas in the space above the liquid escapes, the partial pressure of the CO₂ falls to 0.30 torr, the value in the surrounding atmosphere of the room. What is the solubility of CO₂ in the beverage at this new pressure?Hint: Be sure check your pressure units.

Accepted Answer

Henry's law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. So, as the partial pressure of CO2 decreases, the solubility of CO2 in the beverage will also decrease.The solubility of CO2 in water at 3.750 atm is 0.65 g CO2/100 g H2O. At 0.30 torr, the solubility of CO2 in water is:(0.30 torr / 3.750 atm) * 0.65 g CO2/100 g H2O = 6.8 × 10-5 g CO2/100 g H2O

Question 16

A solution of sodium nitrite is prepared by mixing 3.25 g of NaNO₂ with 12.0 g of water. The percent, by mass, of NaNO₂ is

Accepted Answer

The answer of A solution of sodium nitrite is prepared...

Question 17

A solution of lithium hydroxide is prepared by mixing 2.00 g of LiOH with 10.0 g of water. The percent, by mass, of LiOH is

Accepted Answer

The percent by mass of LiOH is calculated by dividing the mass of LiOH by the total mass of the solution (LiOH + water) and multiplying by 100. (2.00 g / (2.00 g + 10.0 g)) * 100 = 16.7%.

Question 18

How many grams of NaC₂H₃O₂ should be dissolved in 400.0 g of water to prepare a solution that is 11.28% NaC₂H₃O₂ by mass?

Accepted Answer

To find the mass of NaC₂H₃O₂ needed, use the formula: (mass of solute / (mass of solute + mass of solvent)) * 100 = % by mass. Let x be the mass of NaC₂H₃O₂. Then, (x / (x + 400)) * 100 = 11.28. Solving for x gives approximately 50.86 g.

Question 19

A solution of potassium nitrate is prepared by mixing 3.50 g of KNO₃ with 12.0 g of water. The percent, by mass, of KNO₃ is

Accepted Answer

The percent by mass of KNO3 is calculated as:% KNO3 = (mass of KNO3 / total mass of solution) x 100%= (3.50 g / (3.50 g + 12.0 g)) x 100%= 22.6%

Question 20

A glucose solution is prepared by dissolving 5.10 g of glucose, C₆H₁₂O₆, in 110.5 g of water. What is the molality of the glucose solution?

Accepted Answer

Molality (m) is calculated by dividing the moles of solute by the kilograms of solvent. The moles of glucose is 5.10 g / 180.18 g/mol = 0.0283 mol. The mass of water is 110.5 g = 0.1105 kg. Molality = 0.0283 mol / 0.1105 kg = 0.256 m.

Quiz 13: Mixtures at the Molecular Level: Properties of Solutions

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Which response lists all the following pairs that are miscible liquids? Pair 1. octane (C₈H₁₈) and water Pair 2. ammonia (NH₃) and water Pair 3. octane (C₈H₁₈) and carbon tetrachloride (CCl₄)

Concerning the process of separating of a solid substance into its component units (molecules or ions) ,

Concerning the solvation step of the solution process,

KBr has a lattice energy of -682 kJ/mol and a hydration energy of -657 kJ/mol. Using this information, what is the heat of solution, $\Delta$ H_sol, for KBr?Hint: What happens to the crystal lattice when an ionic compound dissolves?

A solution in a beaker has some undissolved solute lying on the bottom of the beaker. If the rate of crystallization exceeds the rate of dissolution of the excess solute, the solution is described as

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of crystallization is equal to the rate of dissolution of the excess solute, the solution is described as

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of dissolution of the solute exceeds the rate of crystallization, the solution is described as

A solution is sitting undisturbed on a side shelf in the laboratory. A small crystal of the same solute of which the solution is made was gently dropped into the solution. Suddenly, a mass of crystals forms and settles to the bottom of the container. The solution is, or must have been

Which of the following will always cause an increase in the solubility of a gas in a solvent in which the gas does not react with the solvent to form a new substance?

The solubility of O₂ in water is approximately 0.00380 g L^-1 when the temperature is 25.0°C and the partial pressure of gaseous oxygen is 760. torr. What will the solubility of oxygen be if the oxygen pressure is adjusted to 1000 torr?

A solution is made by mixing 138.2 grams of ethanol, C₂H₆O, (46.069 g mol^-1) ; 103.6 grams of water (18.015 g mol^-1) , and 80.11 grams of methanol, CH₄O, (32.042 g mol^-1) . What is the mole fraction of methanol in the mixture?

A solution of sodium nitrite is prepared by mixing 3.25 g of NaNO₂ with 12.0 g of water. The percent, by mass, of NaNO₂ is

A solution of lithium hydroxide is prepared by mixing 2.00 g of LiOH with 10.0 g of water. The percent, by mass, of LiOH is

How many grams of NaC₂H₃O₂ should be dissolved in 400.0 g of water to prepare a solution that is 11.28% NaC₂H₃O₂ by mass?

A solution of potassium nitrate is prepared by mixing 3.50 g of KNO₃ with 12.0 g of water. The percent, by mass, of KNO₃ is

A glucose solution is prepared by dissolving 5.10 g of glucose, C₆H₁₂O₆, in 110.5 g of water. What is the molality of the glucose solution?

Quiz 13: Mixtures at the Molecular Level: Properties of Solutions

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Wax is a solid mixture of hydrocarbon compounds consisting of molecules with long chains of carbon atoms. Which solvent would you expect to be most capable of dissolving wax?

Which response lists all the following pairs that are miscible liquids? Pair 1. octane (C8H18) and water Pair 2. ammonia (NH3) and water Pair 3. octane (C8H18) and carbon tetrachloride (CCl4)

Concerning the process of separating of a solid substance into its component units (molecules or ions) ,

Concerning the solvation step of the solution process,

KBr has a lattice energy of -682 kJ/mol and a hydration energy of -657 kJ/mol. Using this information, what is the heat of solution, Δ\DeltaΔ Hsol, for KBr?Hint: What happens to the crystal lattice when an ionic compound dissolves?

A solution in a beaker has some undissolved solute lying on the bottom of the beaker. If the rate of crystallization exceeds the rate of dissolution of the excess solute, the solution is described as

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of crystallization is equal to the rate of dissolution of the excess solute, the solution is described as

A solution in a beaker has some un-dissolved solute lying on the bottom of the beaker. If the rate of dissolution of the solute exceeds the rate of crystallization, the solution is described as

A solution is sitting undisturbed on a side shelf in the laboratory. A small crystal of the same solute of which the solution is made was gently dropped into the solution. Suddenly, a mass of crystals forms and settles to the bottom of the container. The solution is, or must have been

Which of the following will always cause an increase in the solubility of a gas in a solvent in which the gas does not react with the solvent to form a new substance?

The solubility of O2 in water is approximately 0.00380 g L-1 when the temperature is 25.0°C and the partial pressure of gaseous oxygen is 760. torr. What will the solubility of oxygen be if the oxygen pressure is adjusted to 1000 torr?

A solution is made by mixing 138.2 grams of ethanol, C2H6O, (46.069 g mol-1) ; 103.6 grams of water (18.015 g mol-1) , and 80.11 grams of methanol, CH4O, (32.042 g mol-1) . What is the mole fraction of methanol in the mixture?

A solution of sodium nitrite is prepared by mixing 3.25 g of NaNO2 with 12.0 g of water. The percent, by mass, of NaNO2 is

A solution of lithium hydroxide is prepared by mixing 2.00 g of LiOH with 10.0 g of water. The percent, by mass, of LiOH is

How many grams of NaC2H3O2 should be dissolved in 400.0 g of water to prepare a solution that is 11.28% NaC2H3O2 by mass?

A solution of potassium nitrate is prepared by mixing 3.50 g of KNO3 with 12.0 g of water. The percent, by mass, of KNO3 is

A glucose solution is prepared by dissolving 5.10 g of glucose, C6H12O6, in 110.5 g of water. What is the molality of the glucose solution?

Which response lists all the following pairs that are miscible liquids? Pair 1. octane (C₈H₁₈) and water Pair 2. ammonia (NH₃) and water Pair 3. octane (C₈H₁₈) and carbon tetrachloride (CCl₄)

KBr has a lattice energy of -682 kJ/mol and a hydration energy of -657 kJ/mol. Using this information, what is the heat of solution, $\Delta$ H_sol, for KBr?Hint: What happens to the crystal lattice when an ionic compound dissolves?

The solubility of O₂ in water is approximately 0.00380 g L^-1 when the temperature is 25.0°C and the partial pressure of gaseous oxygen is 760. torr. What will the solubility of oxygen be if the oxygen pressure is adjusted to 1000 torr?

A solution is made by mixing 138.2 grams of ethanol, C₂H₆O, (46.069 g mol^-1) ; 103.6 grams of water (18.015 g mol^-1) , and 80.11 grams of methanol, CH₄O, (32.042 g mol^-1) . What is the mole fraction of methanol in the mixture?

A solution of sodium nitrite is prepared by mixing 3.25 g of NaNO₂ with 12.0 g of water. The percent, by mass, of NaNO₂ is

How many grams of NaC₂H₃O₂ should be dissolved in 400.0 g of water to prepare a solution that is 11.28% NaC₂H₃O₂ by mass?

A solution of potassium nitrate is prepared by mixing 3.50 g of KNO₃ with 12.0 g of water. The percent, by mass, of KNO₃ is

A glucose solution is prepared by dissolving 5.10 g of glucose, C₆H₁₂O₆, in 110.5 g of water. What is the molality of the glucose solution?