Solutions, Polarity, Concentration, and Thermodynamics

Vocabulary practice flashcards covering solutions, polarity, molecular interactions, concentration units, conversion factors, enthalpy of solution, and temperature scales based on the lecture.

Solvent

The component of a solution that is present in the greater quantity.

Solute

The component of a solution that is present in the lesser quantity.

Phases

The scientific term for the distinct, separate layers that form when immiscible liquids—such as a polar solvent and a nonpolar solvent—are combined.

Polar Compound

A compound composed of molecules held together by polar covalent bonds, creating partially positive and partially negative regions that allow it to mix readily with water and dissolve polar or ionic solids.

Nonpolar Compound

A compound consisting of nonpolar covalent bonds that interacts through weak London forces, avoids mixing with polar solvents, and readily dissolves nonpolar solids.

Hydrophilic

Referring to polar substances that resemble water and interact or mix readily with water.

Hydrophobic

Referring to nonpolar substances that lack polar bonds and do not mix with or dissolve in water.

Phospholipid

A dual-natured molecule featuring a polar head and nonpolar tails that self-assembles into bilayers to separate intracellular water from extracellular water in biological systems.

Dilute Solution

A solution that contains a relatively low amount of dissolved solute per volume of solvent.

Concentrated Solution

A solution that contains a relatively high amount of dissolved solute per volume of solvent.

Molarity ($M$)

A measure of concentration defined as the number of moles of solute divided by the volume of the solution in liters ($\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}$).

Molality

A concentration unit defined as the moles of solute per kilogram of solvent, frequently utilized in industrial manufacturing applications.

Mass Percentage

A concentration unit calculated as the mass of solute divided by the total mass of the solution.

Volumetric Flask

A piece of laboratory glassware designed to contain an exact volume of solution when filled precisely to the faint calibration mark on its neck.

Molar Mass

A conversion factor obtained from the periodic table that enables conversion between the mass of a compound and the number of moles.

Mole-to-Mole Ratio

A conversion factor obtained from a balanced chemical equation that relates the relative stoichiometric amounts of reactants and products.

Density

A conversion factor defined as mass divided by volume ($\text{Density} = \frac{\text{mass}}{\text{volume}}$), used to interconvert the mass and volume of a substance.

Endothermic Dissolution

A dissolving process in which breaking solute-solute and solvent-solvent bonds requires more energy than is released during solute-solvent interaction ($\Delta H > 0$), causing the system to absorb heat and become colder.

Exothermic Dissolution

A dissolving process in which the energy released when solute and solvent molecules interact exceeds the energy required to break their individual bonds ($\Delta H < 0$), causing heat release to the surroundings.

Celsius Scale

A temperature scale created by setting the freezing point of water and the boiling point of water, then dividing the interval into $100$ equal degrees.

Absolute Zero

The theoretical minimum temperature ($0\,\text{K}$) at which there is no energy exchange, molecular vibrations cease, and all particle and electron motion stops.