General Chemistry Comprehensive Study Guide

Chapter 1: Introduction to Chemistry

Distinguishing Elements and Compounds

• Elements are pure substances consisting of only one type of atom.

• Compounds are substances formed from two or more elements chemically bonded in fixed ratios.

• Use particulate diagrams to visually represent the differences between elements, compounds, and mixtures.

Significant Figures

• Significant figures reflect the precision of measured quantities.

• When performing calculations, the number of significant figures in the result should match the least precise measurement.

Chapter 2: Atoms, Molecules, and Ions

Atomic Structure

• Atoms consist of protons, neutrons, and electrons.

• The atomic number (Z) is the number of protons in the nucleus.

• The mass number (A) is the sum of protons and neutrons.

Isotopes and Atomic Mass

• Isotopes are atoms of the same element with different numbers of neutrons.

• Average atomic mass is calculated using the relative abundance and mass of each isotope:

$\text{Average atomic mass} = \sum (\text{fractional abundance} \times \text{isotope mass})$

• Example: If C-12 is 98.9% and C-13 is 1.1%, calculate the average atomic mass.

Periodic Table Organization

• Elements are arranged by increasing atomic number.

• Groups (columns) share similar chemical properties.

Ions

• Cations are positively charged ions (loss of electrons).

• Anions are negatively charged ions (gain of electrons).

Chapter 3: Chemical Reactions and Stoichiometry

Stoichiometry

• Stoichiometry involves quantitative relationships in chemical reactions.

• Use mole ratios from balanced equations to convert between reactants and products.

Gas Laws and Molar Volume

• Standard Temperature and Pressure (STP): 0°C and 1 atm.

• At STP, 1 mole of an ideal gas occupies 22.4 L.

Percent Composition and Empirical Formulas

• Percent composition: $\frac{\text{mass of element}}{\text{total mass}} \times 100$

• Empirical formula: Simplest whole-number ratio of atoms in a compound.

Limiting Reactant and Theoretical Yield

• The limiting reactant is consumed first and determines the maximum amount of product formed.

• Theoretical yield is the calculated maximum product; actual yield is what is obtained experimentally.

Chapter 4: Reactions in Aqueous Solution

Precipitation Reactions

• Solubility rules help predict if a precipitate will form.

• Common precipitates include AgCl, BaSO4, and PbI2.

Net Ionic Equations

• Show only the species that change during the reaction.

Solution Concentration

• Molarity ($M$): $M = \frac{\text{moles of solute}}{\text{liters of solution}}$

Chapter 5: Thermochemistry

Heat and Enthalpy

• Heat ($q$) is energy transferred due to temperature difference.

• Enthalpy ($\Delta H$) is the heat content at constant pressure.

• Endothermic: $\Delta H > 0$ (absorbs heat); Exothermic: $\Delta H < 0$ (releases heat).

Calorimetry

• Used to measure heat changes in chemical reactions.

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

Chapter 6: Electronic Structure of Atoms

Electron Configuration

• Describes the arrangement of electrons in an atom.

• Follow the Aufbau principle, Pauli exclusion principle, and Hund's rule.

• For transition metals, remove electrons from the 4s orbital before 3d when forming cations.

Quantum Numbers

• Principal ($n$), angular momentum ($l$), magnetic ($m_l$), and spin ($m_s$) quantum numbers describe electron properties.

Light and Electromagnetic Radiation

• Energy of a photon: $E = h\nu$

• Wavelength and frequency are inversely related: $c = \lambda\nu$

Chapter 7: Periodic Properties of the Elements

Periodic Trends

• Atomic radius decreases across a period, increases down a group.

• Ionization energy increases across a period, decreases down a group.

• Electron affinity generally becomes more negative across a period.

Group and Period Trends

• Trends are explained by effective nuclear charge and electron shielding.

Chapters 8 & 9: Chemical Bonding and Molecular Geometry

Types of Chemical Bonds

• Ionic bonds: Transfer of electrons from metal to nonmetal.

• Covalent bonds: Sharing of electrons between nonmetals.

• Metallic bonds: Delocalized electrons among metal atoms.

Lewis Structures and Resonance

• Draw Lewis structures to represent valence electrons and bonding.

• Resonance structures depict delocalized electrons in molecules.

VSEPR Theory

• Predicts molecular shapes based on electron pair repulsion.

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

Hybridization

• Atomic orbitals mix to form hybrid orbitals (e.g., sp, sp2, sp3).

Chapter 10: Gases

Gas Laws

• 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: $PV = nRT$

Kinetic Molecular Theory

• Explains gas behavior based on particle motion.

• At the same temperature, all gases have the same average kinetic energy.

Molar Volume

• At STP, 1 mole of gas occupies 22.4 L.

Chapters 11 & 12: Liquids, Solids, and Modern Materials

Intermolecular Forces

• Types: London dispersion, dipole-dipole, hydrogen bonding.

• Stronger forces lead to higher boiling and melting points.

Properties of Solids

• Crystalline solids have ordered structures; amorphous solids lack order.

• Types: ionic, molecular, covalent network, metallic.

Lab Techniques and Procedures

• Understand basic lab procedures and calculations (e.g., titrations, filtrations).

• Know properties of common acids, bases, and salts.

Graphs and Spectroscopy

• Interpret Maxwell-Boltzmann temperature distribution graphs.

• Understand heating curves and phase changes.

• Basics of Photoelectron Spectroscopy (PES) and Mass Spectrometry.

• Draw particulate diagrams for chemical reactions, always accounting for excess reactants.

Additional info: This guide covers foundational topics in general chemistry, including atomic structure, chemical bonding, stoichiometry, periodic trends, gas laws, and laboratory techniques. It is suitable for exam preparation and review.