General Chemistry Fundamentals: Matter, Energy, Atomic Structure, and Chemical Reactions

Chapter 1: Matter and Energy

Properties of Matter

Matter is anything that has mass and occupies space. Its properties can be measured and classified to help identify substances and predict their behavior.

• Volume: The amount of space a substance occupies, typically measured in liters (L) or cubic centimeters (cm3).

• Temperature: A measure of the average kinetic energy of particles in a substance. Common units are Celsius (°C), Kelvin (K), and Fahrenheit (°F).

• Density: The mass per unit volume of a substance. $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

Significant Figures and Operations

Significant figures reflect the precision of measured quantities. When performing calculations, the number of significant figures in the result should reflect the least precise measurement.

• Addition/Subtraction: Result should have the same number of decimal places as the measurement with the fewest decimal places.

• Multiplication/Division: Result should have the same number of significant figures as the measurement with the fewest significant figures.

Conversion Factors and Prefixes

Conversion factors are used to change units in measurements. Prefixes indicate powers of ten and are commonly used in the metric system.

• Common Prefixes: kilo- (k, $10^3$), centi- (c, $10^{-2}$), milli- (m, $10^{-3}$), micro- ($\mu$, $10^{-6}$), nano- (n, $10^{-9}$)

• Example: To convert 5.0 cm to meters: $5.0\ \text{cm} \times \frac{1\ \text{m}}{100\ \text{cm}} = 0.050\ \text{m}$

Chapter 2: Atomic Structure and Periodicity

Subatomic Particles

Atoms are composed of three main subatomic particles: protons, neutrons, and electrons.

• Proton: Positively charged particle found in the nucleus.

• Neutron: Neutral particle found in the nucleus.

• Electron: Negatively charged particle found outside the nucleus.

Atomic Symbols and Isotopes

Atomic symbols represent elements, and isotopes are atoms of the same element with different numbers of neutrons.

• Atomic Symbol: One or two-letter abbreviation for an element (e.g., H for hydrogen, O for oxygen).

• Isotope: Atoms with the same number of protons but different numbers of neutrons.

• Example: $^{12}\text{C}$ and $^{13}\text{C}$ are isotopes of carbon.

Atomic Mass

The atomic mass is the weighted average mass of all naturally occurring isotopes of an element.

• Formula: $\text{Atomic Mass} = \sum (\text{Fractional Abundance} \times \text{Isotope Mass})$

Periodic Table Trends

The periodic table organizes elements by increasing atomic number and reveals periodic trends in properties.

• Atomic Radius: Generally decreases across a period and increases down a group.

• Ionization Energy: Generally increases across a period and decreases down a group.

• Electronegativity: Tendency of an atom to attract electrons; increases across a period, decreases down a group.

Chapter 3: Ionic Compounds and Chemical Formulas

Writing Ionic Compounds

Ionic compounds are formed from the electrostatic attraction between cations and anions. Their formulas reflect the ratio of ions needed to balance charges.

• Cation: Positively charged ion (usually a metal).

• Anion: Negatively charged ion (usually a nonmetal).

• Example: Sodium chloride: $\text{Na}^+ + \text{Cl}^- \rightarrow \text{NaCl}$

Naming Ionic Compounds

• Name the cation first, then the anion.

• For transition metals, indicate the charge with Roman numerals (e.g., Fe2+ is iron(II)).

• Polyatomic ions retain their names (e.g., $\text{NO}_3^-$ is nitrate).

Balancing Chemical Reactions

Balancing chemical equations ensures the law of conservation of mass is obeyed.

• Adjust coefficients to have equal numbers of each atom on both sides of the equation.

• Example: $2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}$

Chapter 4: Stoichiometry and Limiting Reactants

Limiting Reactants

The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the amount of product formed.

• Calculate moles of each reactant.

• Determine which reactant produces the least amount of product.

• Example: If 2 mol A reacts with 3 mol B, and the reaction requires 1 mol A per 2 mol B, B is the limiting reactant.

Chapter 5: Solutions and Solubility

Solubility and Exchange Reactions

Solubility refers to the ability of a substance to dissolve in a solvent. Exchange (double displacement) reactions often occur in aqueous solutions.

• Solubility Rules: Most nitrates, alkali metal salts, and ammonium salts are soluble.

• Exchange Reaction Example: $\text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} (s) + \text{NaNO}_3$

Electrolytes

Electrolytes are substances that conduct electricity when dissolved in water.

• Strong Electrolytes: Completely dissociate in solution (e.g., NaCl).

• Weak Electrolytes: Partially dissociate (e.g., acetic acid).

Concentration and Dilution

Concentration measures the amount of solute in a given volume of solution. Dilution decreases concentration by adding more solvent.

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

• Dilution Equation: $M_1V_1 = M_2V_2$

• Example: To dilute 1.0 M solution to 0.5 M, use equal volumes of solution and solvent.

Additional info:

• Some content inferred from context and standard General Chemistry curriculum.

• Topics grouped and expanded for clarity and completeness.