exam 1 chem

Comprehensive vocabulary flashcards covering properties of liquids, phase changes, solutions, colligative properties, and solid crystal structures based on chemistry lecture notes.

Pure Covalent Bond

A bond between neutral atoms held together by equally shared electrons.

Polar Covalent Bond

A bond between partially charged atoms held together by unequally shared electrons.

Ionic Bond

A bond between oppositely charged ions held together by electrostatic attraction.

Intermolecular Forces

The attractive forces that hold particles together in condensed phases.

van der Waals Forces

Attractive forces that act between atoms or molecules in a pure substance, including dipole-dipole forces, hydrogen bonding, and London dispersion forces.

Dipole-Dipole Forces

Electrostatic interactions between polar molecules.

Hydrogen Bonding

A special type of dipole-dipole interaction occurring only in molecules containing $\text{H}$ bonded to a small, highly electronegative atom, such as $\text{N}$, $\text{O}$, or $\text{F}$.

Instantaneous Dipole

A fleeting, temporary dipole created when a molecule experiences a non-uniform distribution of electron density at a given point in time.

London Dispersion Forces

Weak attractive forces resulting from instantaneous dipoles inducing temporary dipoles in neighboring molecules.

Polarizability

The ease with which the distribution of electron density in a molecule can be distorted to form a dipole.

Viscosity

A measure of a fluid's resistance to flow.

Surface Tension

The ability of a liquid to resist changes in surface area.

Heat of Fusion ($\Delta H_{\text{fusion}}$)

The amount of energy required to overcome enough intermolecular forces to convert one mole of a solid to a liquid.

Heat of Vaporization ($\Delta H_{\text{vap}}$)

The amount of energy required to overcome enough intermolecular forces to convert one mole of a liquid to a gas.

Enthalpy of Sublimation ($\Delta H_{\text{sub}}$)

The energy required to sublime $1\,\text{mole}$ of a solid directly into a gas, defined by the relationship $\Delta H_{\text{sub}} = \Delta H_{\text{fusion}} + \Delta H_{\text{vap}}$.

Vapor Pressure

The partial pressure of a gas at equilibrium with its liquid phase.

Volatile

Describing substances with weak intermolecular forces that readily escape into the gas phase and exhibit high vapor pressures at room temperature.

Clausius-Clapeyron Equation

An equation expressing the linear relationship between the natural log of vapor pressure and inverse temperature: $\ln(P) = -\frac{\Delta H_{\text{vap}}}{RT} + C$ or $\ln\left(\frac{P_1}{P_2}\right) = \frac{\Delta H_{\text{vap}}}{R}\left(\frac{1}{T_2} - \frac{1}{T_1}\right)$.

Solution

A homogeneous mixture whose composition is the same throughout.

Solvent

The component of a solution present in the greater extent.

Solute

The component of a solution present in the lesser extent.

Miscible

Describing two liquids that are completely soluble in each other in all proportions.

Molarity ($M$)

A concentration unit defined as $\text{molarity} = M = \frac{\text{moles of solute}}{\text{liters of solution}}$.

Mole Fraction ($\chi_A$)

The ratio of moles of component $A$ to the sum of moles of all components in a mixture: $\chi_A = \frac{\text{moles of } A}{\text{sum of moles of all components}}$.

Percent by Mass

The concentration expressed as $\text{percent by mass} = \frac{\text{mass of solute}}{\text{mass of solute} + \text{mass of solvent}} \times 100\%$.

Molality ($m$)

A temperature-independent concentration unit defined as $\text{molality} = m = \frac{\text{moles of solute}}{\text{mass of solvent (in kg)}}$.

Saturated Solution

A solution containing the maximum possible amount of dissolved solute at equilibrium.

Supersaturated Solution

A solution containing a greater-than-equilibrium amount of solute.

Henry's Law

States that the solubility of a gas in a liquid is proportional to the pressure of the gas over the solution, given by $c = k \times P$.

Colligative Properties

Solution properties that depend on the amount of a dissolved solute but not on its chemical identity.

Raoult's Law

States that the vapor pressure of a solvent above a solution containing a non-volatile solute is given by $P_{\text{soln}} = P_{\text{solv}} \times \chi_{\text{solv}}$.

van 't Hoff Factor ($i$)

The ratio of moles of particles in solution to moles of solute dissolved: $i = \frac{\text{moles of particles in solution}}{\text{moles of solute dissolved}}$.

Ion Pair

A species made up of one or more cations and one or more anions held together by electrostatic forces in solution.

Boiling-Point Elevation

The increase in boiling point of a solution relative to the pure solvent, calculated using $\Delta T_{\text{b}} = i \times K_{\text{b}} \times m$.

Freezing-Point Depression

The decrease in freezing point of a solution relative to the pure solvent, calculated using $\Delta T_{\text{f}} = i \times K_{\text{f}} \times m$.

Osmosis

The passage of solvent through a semipermeable membrane from the less concentrated side to the more concentrated side.

Osmotic Pressure ($\pi$)

The amount of pressure necessary to cause osmosis to stop, given by $\pi = i \times M \times R \times T$.

Crystalline Solid

A solid possessing rigid and long-range order whose atoms, molecules, or ions occupy specific positions in a lattice structure.

Amorphous Solid

A solid that lacks a regular three-dimensional arrangement of atoms, such as glass and rubber.

Covalent Network Solid

A crystal in which atoms are held together in an extensive three-dimensional network entirely by covalent bonds.

Molecular Crystal

A crystalline solid whose lattice points are occupied by molecules held together by van der Waals forces.

Metallic Crystal

A crystalline solid where every lattice point is occupied by a metal atom, characterized by electron sharing in an electron sea.

Unit Cell

The basic repeating structural unit of a crystalline solid.

Coordination Number

The number of nearest-neighbor atoms in a crystal lattice.

Primitive Cubic Unit Cell

A simple cubic structure with a coordination number of $6$, $52\%$ space used, and $1$ net atom per unit cell.

Body-Centered Cubic Cell

A cubic cell structure where spheres rest in depressions between spheres in the previous layer, having a coordination number of $8$, $68\%$ space used, and $2$ net atoms per unit cell.

Face-Centered Cubic Cell

A cubic closest-packed structure with a coordination number of $12$, $74\%$ space used, and $4$ net atoms per unit cell.

Hexagonal Closest-Packed Structure

A closest packing crystal structure with an $ABAB$ stacking arrangement, having a coordination number of $12$ and $74\%$ space used.

Cubic Closest-Packed Structure

A closest packing crystal structure with an $ABCABC$ stacking arrangement that corresponds to a face-centered cubic unit cell, having a coordination number of $12$ and $74\%$ space used.