General Chemistry: Comprehensive Study Notes (Matter, Atoms, Bonding, Gases, Thermochemistry, and More)

Matter, Measurement, and Problem Solving

Units, Moles, and Molar Mass

Understanding the relationships between mass, moles, and molar mass is fundamental in chemistry. The mole is a counting unit that relates the mass of a substance to the number of particles it contains.

• Mole (mol): The amount of substance containing Avogadro's number (6.022 × 1023) of particles.

• Molar Mass (g/mol): The mass of one mole of a substance, numerically equal to the sum of the atomic masses of its constituent atoms.

• Key Equation: $ext{Moles} = rac{ ext{Mass (g)}}{ ext{Molar Mass (g/mol)}}$

• Example: To convert 1.00 g of Na2O to moles: $rac{1.00 ext{ g Na}_2 ext{O}}{61.979 ext{ g/mol}} = 0.0161 ext{ mol}$

Atoms, Elements, and Periodic Properties

Atomic Structure and Ionization Energy

Atoms consist of protons, neutrons, and electrons. The arrangement of electrons determines chemical properties and periodic trends.

• Ionization Energy (IE): The energy required to remove an electron from a gaseous atom or ion.

• Trends: IE increases across a period and decreases down a group.

• Successive Ionization Energies: Removing each subsequent electron requires more energy, especially after removing all valence electrons.

• Example: $X(g) ightarrow X^+(g) + e^- ext{ (IE}_1)$ $X^+(g) ightarrow X^{2+}(g) + e^- ext{ (IE}_2)$

Electron Configurations

• Electrons fill orbitals in order of increasing energy (Aufbau principle).

• Valence electrons are those in the outermost shell and are responsible for chemical reactivity.

Molecules and Compounds

Lewis Structures and Molecular Geometry

• Lewis Structure: A diagram showing the arrangement of valence electrons among atoms in a molecule.

• Electron Geometry: Determined by the number of electron domains (bonding and lone pairs) around the central atom.

• Example: For NH3, the electron geometry is tetrahedral.

Resonance

• Some molecules are best represented by two or more resonance forms, which differ only in the placement of electrons.

• Example: O3 (ozone) has two resonance structures.

Chemical Reactions and Stoichiometry

Balancing Equations and Limiting Reactants

• Balanced Equation: The number of atoms of each element is the same on both sides of the equation.

• Limiting Reactant: The reactant that is completely consumed first, limiting the amount of product formed.

• Example: $ext{Fe}_2 ext{O}_3 + 3 ext{CO} ightarrow 2 ext{Fe} + 3 ext{CO}_2$

Stoichiometric Calculations

• Use mole ratios from the balanced equation to convert between amounts of reactants and products.

Introduction to Solutions and Aqueous Solutions

Concentration Units

• Molarity (M): Moles of solute per liter of solution. $M = rac{ ext{mol solute}}{ ext{L solution}}$

• Example: 0.10 mol Cl- in 0.50 L solution = 0.20 M

Beer-Lambert Law

• Relates absorbance (A) to concentration (c): $A = ext{Slope} imes c + ext{Intercept}$

• Used to determine unknown concentrations from absorbance measurements.

Gases

Gas Laws

• Ideal Gas Law: $PV = nRT$ Where P = pressure, V = volume, n = moles, R = gas constant, T = temperature (K).

• Example: Calculate moles of gas at STP: $n = rac{PV}{RT}$

Kinetic Molecular Theory

• Describes the motion of gas particles and explains properties such as pressure and temperature.

• Speed distribution graphs show the range of molecular speeds at a given temperature.

Thermochemistry

Heat, Work, and Calorimetry

• Heat (q): Energy transferred due to temperature difference.

• Calorimetry Equation: $q = m c riangle T$ Where m = mass, c = specific heat, $riangle T$ = temperature change.

• Example: Calculating final temperature after mixing substances.

Enthalpy and Bond Energies

• Enthalpy Change ($riangle H$): Heat change at constant pressure.

• Bond Enthalpy: Energy required to break one mole of a bond in a molecule.

• Example: $riangle H = ext{Bonds broken} - ext{Bonds formed}$

Chemical Bonding I & II: Lewis Model, VSEPR, and MO Theory

Bond Types and Hybridization

• Sigma (σ) and Pi (π) Bonds: Single bonds are sigma; double and triple bonds contain one sigma and one or two pi bonds, respectively.

• Hybridization: Mixing of atomic orbitals to form new hybrid orbitals. Example: sp, sp2, sp3 hybridization.

Bond Order and Strength

• Triple bonds are shorter and stronger than double or single bonds.

• Bond order is related to the number of shared electron pairs between two atoms.

Liquids, Solids, and Intermolecular Forces

Alloys and Structures

• Alloy: A mixture of two or more elements, at least one of which is a metal.

• Interstitial alloys form when atoms of different sizes combine, as in Ni and H.

Lab Techniques and Procedures

Experimental Design and Data Analysis

• Use of calorimeters to measure heat changes in reactions.

• Graphical analysis to determine concentration from absorbance data.

• Understanding sources of error and experimental uncertainty.

Mathematical Operations and Functions

Significant Figures and Calculations

• Maintain correct significant figures in all calculations.

• Use dimensional analysis for unit conversions.

Additional info:

• Some explanations and context have been expanded for clarity and completeness.

• Tables and graphs referenced in the questions have been described in text for accessibility.