Question 1

115.0 grams of calcium chloride are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the calcium chloride solution?

Accepted Answer

The molar mass of calcium chloride (CaCl2) is approximately 110.98 g/mol. The number of moles of CaCl2 is 115.0 g / 110.98 g/mol = 1.036 moles. The concentration is moles/volume = 1.036 moles / 1.5 L = 0.6907 M.

Question 2

96.5 grams of an unknown substance were diluted with water in a 1.000 L volumetric flask. It was determined that the concentration of the substance was 1.22 M. What is the molar mass of the unknown substance?

Accepted Answer

B

Question 3

Equal volumes of ethanol (C₂H₅OH) and water are mixed. If the density of water is 1.00 g·cm^-³ and that of ethanol is 0.789, what is the mole fraction of ethanol in the mixture?

Accepted Answer

D

Question 4

120.0 grams of calcium nitrate are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the nitrate ions in solution?

Accepted Answer

The correct answer is A because the concentration of the nitrate ions in solution can be calculated using the formula:Concentration = (Moles of solute) / (Volume of solution in liters)The moles of calcium nitrate can be calculated using its molar mass, which is 164.09 g/mol:Moles of calcium nitrate = 120.0 g / 164.09 g/mol = 0.731 molThe volume of the solution is 1.5 L.Therefore, the concentration of the nitrate ions in solution is:Concentration = 0.731 mol / 1.5 L = 0.4875 MSince the nitrate ion has a charge of -1, the concentration of the nitrate ions in solution is also 0.4875 M.

Question 5

50.0 grams of sodium benzoate (mw 144.1053 g·mol^-¹) is diluted into enough water to give a 0.95 molal solution. If the density of the solution is .985 g·cm^-³, what is the mass of water that was added?

Accepted Answer

To find the mass of water, first calculate the moles of sodium benzoate: 50.0 g / 144.1053 g/mol = 0.347 moles. Since the solution is 0.95 molal, 0.347 moles of sodium benzoate are dissolved in 0.347 / 0.95 = 0.365 kg of water, which is 365 grams.

Question 6

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: Cr₂O₇²^-(aq) + H⁺(aq) + I^-(aq) → Cr³⁺(aq) + H₂O(l) + I₃^-(aq)

Accepted Answer

The answer of Find the (integer) stoichiometry coefficients for the...

Question 7

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: IO₃^-(aq) + S₂O₃²^-(aq) + H⁺(aq) → I^-(aq) + S₄O₇²^-(aq) + H₂O(l)

Accepted Answer

The balanced equation is: 2 IO3^- + 6 S2O3^2- + 6 H^+ → 2 I^- + 3 S4O7^2- + 3 H2O.

Question 8

Some sodium hydroxide pellets were placed in an Erlenmeyer flask and dissolved in approximately 50 ml of water. This solution was then transferred to a buret. 3.00 ml of 1.0 molar nitric acid was diluted into approximately 50 ml of water in another flask. It required 22.67 ml of the sodium hydroxide solution to titrate the dilute nitric acid solution to an endpoint. What can you say about the mass of sodium hydroxide pellets initially added to the Erlenmeyer flask?

Accepted Answer

The answer of Some sodium hydroxide pellets were placed in...

Question 9

How many ml of 0.1506 M NaOH are required to reach the endpoint in a titration with 30.00 ml of 0.2215 M HCl?

Accepted Answer

The answer of How many ml of 0.1506 M NaOH...

Question 10

Which, if any, of the following would you expect to readily dissolve in water?

Accepted Answer

The answer of Which, if any, of the following would...

Question 11

According to the Arrhenius theory, which of the following is a base?

Accepted Answer

According to the Arrhenius theory, a base is a substance that increases the concentration of hydroxide ions (OH⁻) in aqueous solution. Ca(OH)₂ is a base because it dissociates in water to produce hydroxide ions.

Question 12

An unknown amount of toluene (bp 110.6 C) and benzene (bp 80.1 C) are mixed and the vapor pressure over the mixture measured. 100 grams of toluene is then added to the mixture and the vapor pressure measured again. Will the new vapor pressure be:

Accepted Answer

Adding more toluene, which has a higher boiling point and lower vapor pressure than benzene, will decrease the overall vapor pressure of the mixture.

Question 13

A mixture is prepared by mixing 100.0 grams of ethanol (C₂H₆O) with 30.0 grams of acetone (C₃H₆O). At 25°C the vapor pressures of pure ethanol and acetone are 59 Torr and 231 Torr respectively. What will be the total vapor pressure over the mixture at this temperature?

Accepted Answer

The total vapor pressure is calculated using Raoult's Law. First, calculate the mole fraction of each component. Then, use the mole fractions and the vapor pressures of the pure components to find the partial pressures, and sum them to get the total vapor pressure.

Question 14

Exhibit 11-1
The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate.
Refer to Exhibit 11-1. Which of the following represents a balanced net ionic chemical equation for this reaction?

Accepted Answer

The net ionic equation only includes the ions that participate in forming the precipitate. In this case, Pb²⁺ and SO₄^2- combine to form the insoluble PbSO₄ precipitate.

Question 15

Exhibit 11-1
The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate.
Refer to Exhibit 11-1. What are the spectator ions in this reaction?

Accepted Answer

In the reaction between lead nitrate and sodium sulfate, the lead ions (Pb^2+) and sulfate ions (SO4^2-) form the precipitate lead sulfate (PbSO4). The nitrate ions (NO3^-) and sodium ions (Na^+) do not participate in the formation of the precipitate and remain in solution as spectator ions.

Question 16

On a per-mole basis, which of the following, when dissolved in water, will lower the freezing point most?

Accepted Answer

FeCl₃ dissociates into four ions (Fe³⁺ and 3 Cl^-), which is the highest number of ions among the given options, leading to the greatest depression of the freezing point according to colligative properties.

Question 17

30.0 g of a binary salt is dissolved in enough water to give a final volume of 800.0 ml. The freezing point of the water drops by 2.40°C. What is the molar mass of the binary salt?

Accepted Answer

The answer of 30.0 g of a binary salt is...

Question 18

What is the expected boiling point of a solution made by combining 400.0 g of water with 100.0 g of Na₂CO₃?

Accepted Answer

The boiling point of a solution is elevated by the addition of a non-volatile solute. The boiling point elevation is directly proportional to the molality of the solution. The molality of a solution is defined as the number of moles of solute per kilogram of solvent. In this case, the solvent is water and the solute is Na₂CO₃. The molar mass of Na₂CO₃ is 105.99 g/mol. Therefore, the number of moles of Na₂CO₃ in 100.0 g is 100.0 g / 105.99 g/mol = 0.944 mol. The mass of water in the solution is 400.0 g. Therefore, the molality of the solution is 0.944 mol / 0.400 kg = 2.36 mol/kg. The boiling point elevation constant for water is 0.512 °C/mol/kg. Therefore, the boiling point elevation is 2.36 mol/kg x 0.512 °C/mol/kg = 1.21 °C. The boiling point of pure water is 100.0 °C. Therefore, the expected boiling point of the solution is 100.0 °C + 1.21 °C = 101.2 °C.

Question 19

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO4 into 600.0g. of water. Refer to Exhibit 11-2. What is the molality of the KMnO₄ in the 800.0 gram solution?

Accepted Answer

Molality (m) is calculated as moles of solute per kilogram of solvent. First, calculate the moles of KMnO4: 200.0 g / 158.04 g/mol = 1.265 moles. The mass of the solvent (water) is 600.0 g or 0.600 kg. Molality = 1.265 moles / 0.600 kg = 2.109 m.

Question 20

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO₄ into 600.0g. of water. Refer to Exhibit 11-2. What is the mole fraction of MnO₄^- ions in the solution?

Accepted Answer

To find the mole fraction of MnO4- ions, first calculate the moles of KMnO4 (molar mass = 158.04 g/mol) and water (molar mass = 18.02 g/mol). Moles of KMnO4 = 200.0 g / 158.04 g/mol = 1.265 moles. Moles of water = 600.0 g / 18.02 g/mol = 33.3 moles. The mole fraction of MnO4- is the moles of KMnO4 divided by the total moles (KMnO4 + water), which is 1.265 / (1.265 + 33.3) = 0.0353.

Quiz 11: Solutions

115.0 grams of calcium chloride are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the calcium chloride solution?

96.5 grams of an unknown substance were diluted with water in a 1.000 L volumetric flask. It was determined that the concentration of the substance was 1.22 M. What is the molar mass of the unknown substance?

Equal volumes of ethanol (C₂H₅OH) and water are mixed. If the density of water is 1.00 g·cm^-³ and that of ethanol is 0.789, what is the mole fraction of ethanol in the mixture?

120.0 grams of calcium nitrate are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the nitrate ions in solution?

50.0 grams of sodium benzoate (mw 144.1053 g·mol^-¹) is diluted into enough water to give a 0.95 molal solution. If the density of the solution is .985 g·cm^-³, what is the mass of water that was added?

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: Cr₂O₇²^-(aq) + H⁺(aq) + I^-(aq) → Cr³⁺(aq) + H₂O(l) + I₃^-(aq)

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: IO₃^-(aq) + S₂O₃²^-(aq) + H⁺(aq) → I^-(aq) + S₄O₇²^-(aq) + H₂O(l)

How many ml of 0.1506 M NaOH are required to reach the endpoint in a titration with 30.00 ml of 0.2215 M HCl?

Which, if any, of the following would you expect to readily dissolve in water?

According to the Arrhenius theory, which of the following is a base?

An unknown amount of toluene (bp 110.6 C) and benzene (bp 80.1 C) are mixed and the vapor pressure over the mixture measured. 100 grams of toluene is then added to the mixture and the vapor pressure measured again. Will the new vapor pressure be:

A mixture is prepared by mixing 100.0 grams of ethanol (C₂H₆O) with 30.0 grams of acetone (C₃H₆O) . At 25°C the vapor pressures of pure ethanol and acetone are 59 Torr and 231 Torr respectively. What will be the total vapor pressure over the mixture at this temperature?

Exhibit 11-1 The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate. Refer to Exhibit 11-1. Which of the following represents a balanced net ionic chemical equation for this reaction?

Exhibit 11-1 The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate. Refer to Exhibit 11-1. What are the spectator ions in this reaction?

On a per-mole basis, which of the following, when dissolved in water, will lower the freezing point most?

30.0 g of a binary salt is dissolved in enough water to give a final volume of 800.0 ml. The freezing point of the water drops by 2.40°C. What is the molar mass of the binary salt?

What is the expected boiling point of a solution made by combining 400.0 g of water with 100.0 g of Na₂CO₃?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO4 into 600.0g. of water. Refer to Exhibit 11-2. What is the molality of the KMnO₄ in the 800.0 gram solution?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO₄ into 600.0g. of water. Refer to Exhibit 11-2. What is the mole fraction of MnO₄^- ions in the solution?

Quiz 11: Solutions

115.0 grams of calcium chloride are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the calcium chloride solution?

96.5 grams of an unknown substance were diluted with water in a 1.000 L volumetric flask. It was determined that the concentration of the substance was 1.22 M. What is the molar mass of the unknown substance?

Equal volumes of ethanol (C2H5OH) and water are mixed. If the density of water is 1.00 g·cm-3 and that of ethanol is 0.789, what is the mole fraction of ethanol in the mixture?

120.0 grams of calcium nitrate are weighed out and placed into a 1.5 L volumetric flask and the flask filled to the mark. What is the concentration of the nitrate ions in solution?

50.0 grams of sodium benzoate (mw 144.1053 g·mol-1) is diluted into enough water to give a 0.95 molal solution. If the density of the solution is .985 g·cm-3, what is the mass of water that was added?

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: Cr2O72-(aq) + H+(aq) + I-(aq) → Cr3+(aq) + H2O(l) + I3-(aq)

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: IO3-(aq) + S2O32-(aq) + H+(aq) → I-(aq) + S4O72-(aq) + H2O(l)

How many ml of 0.1506 M NaOH are required to reach the endpoint in a titration with 30.00 ml of 0.2215 M HCl?

Which, if any, of the following would you expect to readily dissolve in water?

According to the Arrhenius theory, which of the following is a base?

An unknown amount of toluene (bp 110.6 C) and benzene (bp 80.1 C) are mixed and the vapor pressure over the mixture measured. 100 grams of toluene is then added to the mixture and the vapor pressure measured again. Will the new vapor pressure be:

A mixture is prepared by mixing 100.0 grams of ethanol (C2H6O) with 30.0 grams of acetone (C3H6O) . At 25°C the vapor pressures of pure ethanol and acetone are 59 Torr and 231 Torr respectively. What will be the total vapor pressure over the mixture at this temperature?

Exhibit 11-1 The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate. Refer to Exhibit 11-1. Which of the following represents a balanced net ionic chemical equation for this reaction?

Exhibit 11-1 The following question(s) pertain to the mixing of lead nitrate and sodium sulfate to form a lead sulfate precipitate. Refer to Exhibit 11-1. What are the spectator ions in this reaction?

On a per-mole basis, which of the following, when dissolved in water, will lower the freezing point most?

30.0 g of a binary salt is dissolved in enough water to give a final volume of 800.0 ml. The freezing point of the water drops by 2.40°C. What is the molar mass of the binary salt?

What is the expected boiling point of a solution made by combining 400.0 g of water with 100.0 g of Na2CO3?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO4 into 600.0g. of water. Refer to Exhibit 11-2. What is the molality of the KMnO4 in the 800.0 gram solution?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO4 into 600.0g. of water. Refer to Exhibit 11-2. What is the mole fraction of MnO4- ions in the solution?

Equal volumes of ethanol (C₂H₅OH) and water are mixed. If the density of water is 1.00 g·cm^-³ and that of ethanol is 0.789, what is the mole fraction of ethanol in the mixture?

50.0 grams of sodium benzoate (mw 144.1053 g·mol^-¹) is diluted into enough water to give a 0.95 molal solution. If the density of the solution is .985 g·cm^-³, what is the mass of water that was added?

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: Cr₂O₇²^-(aq) + H⁺(aq) + I^-(aq) → Cr³⁺(aq) + H₂O(l) + I₃^-(aq)

Find the (integer) stoichiometry coefficients for the correctly balanced version of the following reaction: IO₃^-(aq) + S₂O₃²^-(aq) + H⁺(aq) → I^-(aq) + S₄O₇²^-(aq) + H₂O(l)

A mixture is prepared by mixing 100.0 grams of ethanol (C₂H₆O) with 30.0 grams of acetone (C₃H₆O) . At 25°C the vapor pressures of pure ethanol and acetone are 59 Torr and 231 Torr respectively. What will be the total vapor pressure over the mixture at this temperature?

What is the expected boiling point of a solution made by combining 400.0 g of water with 100.0 g of Na₂CO₃?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO4 into 600.0g. of water. Refer to Exhibit 11-2. What is the molality of the KMnO₄ in the 800.0 gram solution?

Exhibit 11-2 The following question(s) pertain to the dissolution of 200.0 g of KMnO₄ into 600.0g. of water. Refer to Exhibit 11-2. What is the mole fraction of MnO₄^- ions in the solution?