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

After spilling vegetable oil on your clothes, you need to remove the stain. You have the following items available to help with the stain: vinegar (CH₃CO₂H); water (H₂O); and toluene (C₆H₆). Which would be the best choice of solvent to remove the oil, and why?

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

At 28.0°C, the vapor pressure of acetonitrile, CH₃CN, is 102.0 torr while that of acetone, C₃H₆O, is 228.9 torr, and for CS₂ the value is 378.7 torr. A three-component solution is made by adding 0.300 moles of CH₃CN and 0.400 moles of C₃H₆O to 0.350 moles of CS₂. The mixture behaves as an ideal mixture. What is the vapor pressure of the solution?Hint: Organizing the given information into moles and mole fraction of each component will help in solving this problem.

A mixture of flour in water would best be classified as

A molecular solute with a molar mass of 50.0 g mol^-1 is dissolved in 500 g of water and the resulting solution has a boiling point of 101.53^°C. How many grams of solute were in the solution $\Delta$ K_b = 0.512 °C m^-1

Which of the following is most likely to be hydrophobic?

Consider a 0.80 M Al(NO₃)₃ solution. What would be the concentration of aluminum and nitrate ions in this solution? The aluminum concentration would be ________ M and the nitrate concentration would be ________ M.

Below is a diagram of vapor pressure versus composition for a mixture of two liquids. The dark straight lines represent the vapor pressure of each pure liquid, while the gray curved line gives the vapor pressure of the mixture. Using this information, which of the following statements is true about the mixture?

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)

An aqueous solution of glycerol, C₃H₈O₃, in which the mole fraction of C₃H₈O₃ is 0.07070 was found to have a density of 1.0350 g mL^-1. What is the molarity of this solution?Hint: Assume one mole of glycerol and solve for moles of water. From there you can find the mass and then volume of the solution.

Substances that dissolve more readily in oils than in water is best classified as ________.

A solution is prepared by mixing 0.3355 moles of NaNO₃ (84.995 g mol^-1)with 235.0 g of water (18.015 g mol^-1). Its density is 1.0733 g mL^-1. What is the molality of the solution?

An aqueous solution which is 12.00% sodium hydroxide by weight has a freezing point of ?10.40°C. What is the observed value of the van't Hoff factor, i, in this solution? K_f = 1.86 °C m^-1.

At 23.0^°C, the vapor pressure of acetonitrile, CH₃CN, is 81.0 torr while that of acetone, C₃H₆O, is 184.5 torr. What is the vapor pressure of a solution that contains 0.550 moles of acetonitrile and 0.350 moles of acetone? (Assume the mixture behaves as an ideal solution.)

What is the osmotic pressure of a solution prepared from 13.7 g of HCl and water to make 0.500 L of solution at 18°C? Assume HCl completely ionizes.Hint: be sure to keep track of units when working this problem.

The Tyndall effect is a light effect that is observed with what kind of solution or mixture?

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

Pure benzene, C₆H₆, has a molar mass of 78.114 g mol⁻¹, a density of 0.8765 g mL⁻¹, a freezing point of 5.45°C, and a boiling point of 80.2°C. Its freezing point depression and boiling point elevation constants are: K_f = 5.07°C m⁻¹; K_b = 2.53°C m⁻¹. A solution was made by taking 33.88 g of an unknown nonelectrolyte and dissolving it in 175.0 g of benzene. The measured freezing point of the solution was -1.65°C. Calculate the molar mass of the unknown substance.Hint: Find molality, then moles, then molar mass, being sure to keep track of units.

A solution is prepared by mixing 0.3355 moles of NaNO₃ with 235.0 g of water. Its density is 1.0733 g mL^-1. If K_f = 1.86 °C m^-1 and the solute is completely ionized, what is the expected freezing point of the solution?Hint: be sure to classify the solute as an electrolyte or non-electrolyte.

Below is a diagram of vapor pressure versus composition for a mixture of two liquids. The dark straight lines represent the vapor pressure of each pure liquid, while the gray curved line gives the vapor pressure of the mixture. Using this information, which of the following statements is true about the mixture?