General Chemistry I: Comprehensive Study Guide

States of Matter

Characteristics of Solids, Liquids, and Gases

• Solids: Definite shape and volume; particles are closely packed in a fixed arrangement.

• Liquids: Definite volume but no definite shape; particles are close but can move past one another.

• Gases: No definite shape or volume; particles are far apart and move freely.

Particle Representation

• Particles can be represented as spheres or dots in diagrams to illustrate their arrangement in different states.

Kinetic Energy and Potential Energy

• Kinetic Energy: Energy of motion; higher in gases than in solids or liquids.

• Potential Energy: Stored energy due to position or interactions between particles.

Characterizing Particles

Mixtures vs. Pure Substances

• Mixtures: Physical combinations of two or more substances; can be separated by physical means.

• Pure Substances: Elements or compounds with a fixed composition.

Atoms, Elements, Compounds, Molecules

• Atom: Smallest unit of an element that retains its properties.

• Element: Substance made of only one kind of atom.

• Compound: Substance composed of two or more elements chemically combined.

• Molecule: Two or more atoms bonded together.

Density

Particle Representation

• Density is the mass per unit volume of a substance.

Density Formula and Application in Laboratory Setting

• The formula for density is: $d = \frac{m}{V}$ where $d$ is density, $m$ is mass, and $V$ is volume.

• Used to identify substances and determine purity in laboratory experiments.

Measurements and Lab Techniques

Units and Correct Digits

• Use SI units (e.g., grams, liters, meters).

• Report measurements with the correct number of significant figures.

Separation Techniques

• Filtration: Separates solids from liquids.

• Distillation: Separates substances based on differences in boiling points.

• Miscibility: Ability of liquids to mix in all proportions.

Heat and Energy

Calorimetry

• Technique to measure heat transfer during chemical or physical processes.

• Uses the equation: $q = mc\Delta T$ where $q$ is heat, $m$ is mass, $c$ is specific heat, and $\Delta T$ is the temperature change.

Specific Heat and Heat of Evaporation

• Specific Heat: Amount of heat required to raise the temperature of 1 gram of a substance by 1°C.

• Heat of Evaporation: Energy required to convert a liquid to a gas at its boiling point.

Types of Heat Flow

• Endothermic: Absorbs heat from surroundings.

• Exothermic: Releases heat to surroundings.

• System vs. surroundings: The system is the part of the universe being studied; everything else is the surroundings.

Gases

Partial Pressure

• Pressure exerted by a single gas in a mixture of gases.

• Dalton's Law: $P_{\text{total}} = P_1 + P_2 + \ldots$

Kinetic Molecular Theory

• Explains the behavior of gases based on particle motion.

• Assumes particles are in constant, random motion and collisions are elastic.

Gas Law Relationships and Formulas

• Boyle's Law: $P_1V_1 = P_2V_2$ (constant T, n)

• Charles's Law: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$ (constant P, n)

• Ideal Gas Law: $PV = nRT$

Periodic Table

Electronegativity, Ionization Energy, Atomic Radius

• Electronegativity: Tendency of an atom to attract electrons in a bond.

• Ionization Energy: Energy required to remove an electron from an atom.

• Atomic Radius: Size of an atom; decreases across a period, increases down a group.

Bonding

Ionic vs. Covalent Bonds

• Ionic Bonds: Transfer of electrons from one atom to another, forming ions.

• Covalent Bonds: Sharing of electrons between atoms.

Bond Polarity and Melting Point

• Bond Polarity: Difference in electronegativity between bonded atoms creates polar bonds.

• Melting Point: Ionic compounds generally have higher melting points than covalent compounds.

Resonance and Lewis Structures

• Resonance: Some molecules can be represented by two or more valid Lewis structures.

• Lewis Structures: Diagrams showing the arrangement of electrons in a molecule.

Molecular Structure

VSEPR Theory

• Valence Shell Electron Pair Repulsion (VSEPR) Theory: Predicts the shapes of molecules based on electron pair repulsion.

• Common shapes: linear, trigonal planar, tetrahedral, trigonal bipyramidal, octahedral.

Intermolecular Forces

• Types: Dispersion (London) forces, dipole-dipole interactions, hydrogen bonding.

• Influence physical properties such as boiling and melting points.

Additional Topics

Difference Between Intermolecular and Intramolecular Forces

• Intramolecular Forces: Forces within a molecule (e.g., covalent bonds).

• Intermolecular Forces: Forces between molecules (e.g., hydrogen bonds).

Polarity and Connection to Macroscopic Properties

• Molecular polarity affects solubility, boiling point, and melting point.

Review and Application to Macroscopic Properties

• Understanding molecular structure and bonding helps explain observable properties of substances.