General Chemistry 1st Semester Final Exam Review Guide – Study Notes

Unit 1: Safety, Measurement, Graphing, Density, and Matter

Measurement and Units of Mass

Understanding the measurement of mass, volume, and length is fundamental in chemistry. The metric system is used for scientific measurements.

• Mass: Measured in grams (g) or kilograms (kg).

• Volume: Measured in liters (L) or milliliters (mL).

• Length: Measured in meters (m) or centimeters (cm).

Example: 1 kg = 1000 g; 1 L = 1000 mL

Density

Density is a physical property that relates the mass of a substance to its volume.

• Definition: Density is mass divided by volume.

$Density = \frac{mass}{volume}$

• Units: Commonly expressed as g/cm3 or g/mL.

• Example: If a block has a mass of 8.9 g and a volume of 1.1 cm3, its density is $\frac{8.9\ g}{1.1\ cm^3} = 8.1\ g/cm^3$.

• Application: Substances with density less than water (1.0 g/mL) will float in water.

Significant Figures

Significant figures reflect the precision of a measured or calculated quantity.

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

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

Unit 2: Gases

Kinetic Molecular Theory

The kinetic molecular theory explains the behavior of gases in terms of particles in motion.

• Gas particles move rapidly and randomly.

• There are negligible forces between particles.

• Collisions between particles are elastic (no energy lost).

• Temperature is proportional to the average kinetic energy of the particles.

Gas Laws

Gas laws describe the relationships between pressure, volume, temperature, and the number of particles.

• Boyle's Law: $P_1V_1 = P_2V_2$ (at constant temperature and number of particles)

• Charles's Law: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$ (at constant pressure and number of particles)

• Avogadro's Law: $\frac{V_1}{n_1} = \frac{V_2}{n_2}$ (at constant temperature and pressure)

• Ideal Gas Law: $PV = nRT$

STP (Standard Temperature and Pressure): 1 atm, 0°C (273 K)

Unit 3: Energy and Thermochemistry

States of Matter and Phase Changes

Matter exists as solids, liquids, or gases, and can change state with the addition or removal of energy.

• Melting: Solid to liquid

• Freezing: Liquid to solid

• Evaporation/Boiling: Liquid to gas

• Condensation: Gas to liquid

• Sublimation: Solid to gas

• Deposition: Gas to solid

Heating Curve: Shows temperature changes as heat is added to a substance, including phase changes where temperature remains constant.

Unit 4: Atoms, Structure, Ions, Isotopes

Atomic Structure

Atoms are composed of protons, neutrons, and electrons.

• Protons: Positively charged, found in the nucleus

• Neutrons: Neutral, found in the nucleus

• Electrons: Negatively charged, found in electron clouds around the nucleus

Atomic Number (Z): Number of protons

Mass Number (A): Number of protons + neutrons

Isotopes: Atoms of the same element with different numbers of neutrons

Ions

• Cations: Positively charged ions (loss of electrons)

• Anions: Negatively charged ions (gain of electrons)

Unit 5: Periodic Table and Trends/Electrons

Periodic Table Organization

The periodic table arranges elements by increasing atomic number and groups elements with similar properties into columns (groups/families).

• Groups: Vertical columns; elements in the same group have similar chemical properties.

• Periods: Horizontal rows

• Metals, Nonmetals, Metalloids: Classified based on properties such as conductivity and luster.

Periodic Trends

• Atomic Radius: Increases down a group, decreases across a period.

• Ionization Energy: Decreases down a group, increases across a period.

• Electronegativity: Decreases down a group, increases across a period.

Unit 6: Naming Compounds and Bonding

Chemical Bonding

Chemical bonds form when atoms share or transfer electrons to achieve stable electron configurations.

• Ionic Bonds: Formed by transfer of electrons from metals to nonmetals.

• Covalent Bonds: Formed by sharing of electrons between nonmetals.

• Lewis Structures: Diagrams that show the arrangement of valence electrons in molecules.

Naming Compounds

• Ionic Compounds: Name the cation first, then the anion (e.g., NaCl = sodium chloride).

• Covalent Compounds: Use prefixes to indicate the number of each atom (e.g., CO2 = carbon dioxide).

Tables

Property	Symbol	SI Unit
Mass	m	kilogram (kg)
Volume	V	liter (L)
Length	l	meter (m)

Additional info: Table inferred from the metric system chart in the file.

Sample Problems and Applications

• Calculate density, mass, or volume using the density formula.

• Apply significant figure rules to calculations.

• Interpret heating/cooling curves and phase diagrams.

• Predict periodic trends and chemical properties based on position in the periodic table.

• Draw and interpret Lewis structures for molecules and ions.