Exam 11: Solutions: Properties and Behavior

Which of the solutions shown here will have the lowest vapor pressure? White circles indicate solvent molecules; black circles indicate molecules of a nonvolatile solute.

A 376 mg sample of a nonelectrolyte compound isolated from throat lozenges was dissolved in water to produce 10.0 mL of a solution at 25°C. The osmotic pressure of this solution was measured and found to be 4.89 atm. What is the molar mass of this compound?

Which one of the ionic compounds below would you expect to have the largest (most negative) lattice energy?

Considering that ideal behavior is not always found in nature, which of the following aqueous solutions would you expect to have the largest van 't Hoff factor?

Identify the following statement as true or false and choose the correct explanation. "For solutions with the same molarity at the same temperature, the pressure needed for reverse osmosis of a sodium chloride solution will always be less than the pressure needed for a calcium chloride solution."

Which of the following is a colligative property? I. osmotic pressure II. vapor pressure III. density IV. freezing point depression V. boiling point

In the diagram below, one beaker contains pure water and the other contains an equal volume of seawater. Seawater has various salts dissolved in it. The beakers are sitting in a totally enclosed chamber, and the outside temperature and pressure are held constant. Identify the statements below about this situation that are not correct. I. Water will be transferred from the pure water beaker to the seawater beaker. II. Water will be transferred from the seawater beaker to the pure water beaker. III. The vapor pressure of the pure water is higher than the vapor pressure of the seawater. IV. Pure water evaporates at a faster rate than seawater. V. Water in the gas phase condenses into both beakers at the same rate.

The pressure inside a bottle of carbonated beverage decreases when it is cooled in a refrigerator. What is the main reason for this change?

Which solution will have the lowest osmotic pressure when measured against pure water?

The arrow in the diagram below indicates the direction of solvent flow through a membrane in osmosis. Which solution, A or B, is more concentrated? Explain your reasoning.

How many moles of solute are there in a 0.155 m glucose solution prepared with 50.0 kg of water?

Which graph best describes how the vapor pressure of a substance varies with temperature according to the Clausius-Clapeyron equation? ln(P) is plotted on the y-axis, and 1/T is plotted on the x-axis. The origin (0, 0) is not necessarily located where the axes cross.

Seawater can be characterized by the following average values. What is the molal concentration of ions in seawater? Explain how you arrived at your answer. density = 1.022 g/mL total mass of ions = 35.17 g/kg concentration of ions = 1.15 M

Calculate the lattice energy of sodium fluoride from the following data: Ionization energy of Na: 496 kJ/mol Electron affinity of F: -328 kJ/mol Energy to vaporize Na: 108 kJ/mol F₂ bond energy: 160 kJ/mol Energy change for the reaction: Na(s) + $\frac { 1 } { 2 }$ F₂(g) $\rightarrow$ NaF(s); $\Delta$ H = -575 kJ

The vapor pressure of an aqueous solution is found to be 24.9 mm Hg at 25°C. What is the mole fraction of solute in this solution? The vapor pressure of water is 25.756 mm Hg at 25°C.

Henry's law constant (mol/L · atm) for oxygen dissolving in blood is 3.74 * 10^-2 mol/(L atm) at body temperature, 37°C. Calculate the molar concentration of oxygen in blood for a scuba diver where the air pressure is 2.0 atm. The mole fraction of oxygen in air is 0.209.

Suppose 100.0 mL of a 2.50 mM NaCl solution were mixed with 100.0 mL of a 3.40 mM MgCl₂ solution at 25°C. Assuming the volumes are additive and using the ideal van 't Hoff factors, what would be the osmotic pressure of the resulting solution?

What physical property is used to separate the hydrocarbon components in petroleum (crude oil)?

Which of the following will require the greatest energy input to separate the ions?

Which one of the ionic compounds below would you expect to have the smallest (least negative) lattice energy?