Case: A solution is a homogeneous mixture of two or more substances. The components of a solution are the solute (substance dissolved) and the solvent (substance doing the dissolving). Solutions can be categorized based on the physical state of the solute and solvent. There are solid, liquid, and gaseous solutions, each exhibiting different properties.
For example, a solid solution, like an alloy (e.g., brass), consists of a solid solute (zinc) dissolved in a solid solvent (copper). In liquid solutions, one liquid is dissolved in another, such as ethanol in water. Gas-liquid solutions, like carbonated drinks, are formed when gas (carbon dioxide) dissolves in a liquid (water). The properties of these solutions, including their solubility, depend on factors like temperature, pressure, and the nature of the solute and solvent.
Questions:
What type of solution is formed when gas dissolves in a liquid?
In which of the following solutions does the solute and solvent both exist in the solid state?
The formation of a solution in which ethanol is dissolved in water is an example of a:
The solubility of a gas in a liquid generally increases with:
Case: Colligative properties are properties of solutions that depend on the number of solute particles present in the solution, rather than the nature of the solute particles. These properties include vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.
For instance, when a non-volatile solute is added to a solvent, the vapor pressure of the solution decreases. This is because the solute particles take up space at the surface, reducing the number of solvent molecules that can escape into the vapor phase. The addition of a solute also raises the boiling point of the solution and lowers its freezing point. Osmotic pressure is the pressure required to stop the flow of solvent into a solution through a semipermeable membrane.
Questions:
Which of the following is a colligative property?
When a non-volatile solute is added to a solvent, the vapor pressure of the solution:
The depression in the freezing point of a solution is directly proportional to:
Osmotic pressure is a colligative property that depends on:
Case: Solubility refers to the amount of solute that can dissolve in a given amount of solvent at a specific temperature and pressure. Several factors affect the solubility of a substance, including temperature, pressure, and the nature of the solute and solvent.
For solids, the solubility typically increases with increasing temperature. In gases, however, solubility decreases as the temperature rises, while the solubility of gases increases with increasing pressure. The chemical nature of the solute and solvent, such as polarity, also plays a significant role. For example, ionic compounds generally dissolve well in polar solvents like water, while non-polar solutes dissolve in non-polar solvents.
Questions:
The solubility of most solid solutes in water increases with:
The solubility of gases in liquids generally decreases with:
Which factor does NOT directly affect the solubility of a solid in a liquid?
Polar solutes dissolve in:
Case: The concentration of a solution refers to the amount of solute dissolved in a given quantity of solvent. Several terms are used to express concentration, including molarity, molality, mass percentage, and mole fraction.
Molarity (M) is the number of moles of solute in one liter of solution, while molality (m) is the number of moles of solute in one kilogram of solvent. Mass percentage is the mass of solute divided by the total mass of the solution, multiplied by 100. Mole fraction is the ratio of the number of moles of a component to the total number of moles in the solution.
These concentration terms are important for calculating and understanding various properties of solutions, such as colligative properties and reaction rates.
Questions:
Molarity is defined as the number of moles of solute per:
Which concentration term is defined as the number of moles of solute per kilogram of solvent?
Mass percentage of a solution is given by:
The mole fraction of a component in a solution is the ratio of:
Case: Raoult's Law relates the vapor pressure of a solution to the vapor pressures of its pure components. According to Raoult’s Law, the partial vapor pressure of each volatile component in a solution is directly proportional to its mole fraction in the solution. This law applies to ideal solutions, where the interactions between the solute and solvent molecules are similar to those between the molecules of the pure components.
When a non-volatile solute is dissolved in a solvent, the vapor pressure of the solution is lower than the vapor pressure of the pure solvent. This is because the non-volatile solute particles occupy space at the surface, reducing the number of solvent molecules able to escape into the vapor phase.
Questions:
Raoult's Law applies to:
According to Raoult’s Law, the partial vapor pressure of a component in a solution is proportional to its:
The vapor pressure of a solution containing a non-volatile solute will be:
The lowering of vapor pressure in a solution is caused by: