Solutions and Properties of Solutions

Flashcards created from lecture notes about solutions, their properties, laws governing them, and practical applications in chemistry.

What is a solution?

A homogeneous mixture of two or more substances.

What are the types of solutions?

Solid, Liquid, and Gaseous solutions.

Define mass percentage (w/w).

Mass % of a component = (Mass of the component in the solution / Total mass of the solution) × 100.

What is volume percentage (v/v)?

Volume % of a component = (Volume of the component / Total volume of solution) × 100.

Define mass by volume percentage (w/V).

Mass by volume percentage is the mass of solute dissolved in 100 mL of the solution.

What is parts per million (ppm)?

Parts per million is the number of parts of the component per million total parts of the solution.

Define mole fraction.

Mole fraction of a component = (Number of moles of the component / Total number of moles of all components).

What is molarity?

Molarity (M) is defined as the number of moles of solute per liter of solution.

Define molality.

Molality (m) is the number of moles of solute per kilogram of solvent.

What does Henry's law state?

At a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the solution.

What is Raoult's law?

The partial vapor pressure of each component in a solution is directly proportional to its mole fraction.

How is vapor pressure of a non-volatile solute affected?

The vapor pressure of the solvent decreases in the presence of a non-volatile solute.

What are colligative properties?

Properties that depend on the number of solute particles, such as vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.

Define ideal solutions.

Solutions that obey Raoult's law over all concentrations.

What is a non-ideal solution?

A solution that deviates from Raoult's law, displaying either positive or negative deviation.

Define positive deviation.

When a solution exhibits higher vapor pressure than predicted by Raoult's law.

Define negative deviation.

When a solution exhibits lower vapor pressure than predicted by Raoult's law.

What is an azeotrope?

A mixture that has the same composition in both liquid and vapor phases and cannot be separated by distillation.

What is osmotic pressure?

The pressure required to stop the flow of solvent into the solution across a semipermeable membrane.

State the van't Hoff factor (i).

The ratio of the observed colligative property to the calculated colligative property.

What is molality related to?

The number of moles of solute per kilogram of solvent.

How does temperature affect solubility of gases?

The solubility of gases in liquids decreases with an increase in temperature.

What happens to molecular characteristics in a liquid solution?

Polar solutes dissolve in polar solvents, and non-polar solutes dissolve in non-polar solvents.

What is dynamic equilibrium in a solution?

A state where the rate of dissolution equals the rate of crystallization.

What is the characteristic of a saturated solution?

A saturated solution contains the maximum amount of solute that can be dissolved at a given temperature.

Define unsaturated solution.

A solution that can still dissolve more solute at the same temperature.

How does pressure affect solubility of gases?

Increasing pressure increases the solubility of gases in liquids.

Provide an example of a gaseous solution.

A mixture of oxygen and nitrogen gases.

What is an ideal gas representation under Henry’s law?

Mole fraction of gas in the solution is proportional to the partial pressure of the gas.

Define freezing point depression.

The decrease in the freezing point of a solvent due to the presence of a solute.

Define boiling point elevation.

The increase in the boiling point of a solvent due to the presence of a solute.

What is the effect of solute on vapor pressure?

The presence of a non-volatile solute lowers the vapor pressure of the solvent.

What is meant by relative lowering of vapor pressure?

The decrease in the vapor pressure of a solvent due to the addition of a solute.

How is molar mass determined using colligative properties?

By relating changes in freezing point or boiling point to the mass of the solute.

What is the significance of colligative properties in chemistry?

They are used to determine molar masses and concentrations of solutions.

Provide an example of a liquid-liquid solution.

Ethanol dissolved in water.

What factors influence dissolution?

The nature of solute and solvent, temperature, and pressure.

How is the mole fraction of solutes calculated in a binary solution?

By dividing the moles of solute by the total moles of all components.

What is the primary cause of positive deviations from Raoult's law?

Weaker A-B interactions than A-A or B-B interactions.

What is the primary cause of negative deviations from Raoult's law?

Stronger A-B interactions than A-A or B-B interactions.

What are the implications of an azeotropic mixture with a minimum boiling point?

It cannot be separated by simple distillation, retaining specific compositions.

List an effect of increasing temperature on solid-liquid solutions.

Increased solubility of solids generally with increased temperature.

What can be concluded about the freezing point of solutions compared to pure solvents?

The freezing point of solutions is lower than that of pure solvents.

Define what is meant by molecular association.

The formation of larger molecules or aggregates from smaller ones, affecting colligative properties.

How does the nature of solute affect boiling point elevation?

Boiling point elevation is related to the concentration of solute particles.

Explain what a hypertonic solution is.

A solution with a higher concentration of solute compared to another solution.

Explain what a hypotonic solution is.

A solution with a lower concentration of solute compared to another solution.

Describe the condition necessary for reverse osmosis.

When pressure greater than osmotic pressure is applied to the solution.

Describe the impact of dissolving a strong electrolyte in water.

It increases the total number of particles in solution, affecting colligative properties.

What are the effects of a non-volatile solute on the vapor pressure of a solvent?

Lowers vapor pressure; the more solute present, the greater the lowering.

Quantify the effect of solute on boiling point elevation using Kb.

�Tb = Kb × m; where Kb is the boiling point elevation constant.

Quantify the effect of solute on freezing point depression using Kf.

�Tf = Kf × m; where Kf is the freezing point depression constant.

Detail the formula relating osmotic pressure to solution concentration.

π = CRT; where π is osmotic pressure, C is concentration, R is gas constant, T is temperature.

What happens to colligative properties if a solute dissociates in solution?

Colligative properties are affected; the observed values differ from the calculated values.

How does a solute that pairs up in solution affect measured molar masses?

Creates a lower observed molar mass than actual due to fewer particles in solution.

Describe the process of osmosis in biological systems.

Movement of solvent across membranes from low to high concentration solutions.

Explain the terms isotonic, hypertonic, and hypotonic in relation to cells and solutions.

Isotonic has equal solute concentrations; hypertonic has more solute, hypotonic has less.

Illustrate an application of Henry’s law.

In soft drinks, CO2 is dissolved under high pressure to increase its concentration.

What occurs when a solute forms an azeotrope with a solvent?

The mixture behaves as a single component at boiling temperature; separation is difficult.

What is a common method to determine molar mass of unknown solute?

Using osmotic pressure and van't Hoff's equation.