Claire’s Semester 2, Honors Chemistry 1, Study Guide_

Moles

A mole is 6.02 x 10^23 representative particles of a substance and is the SI unit for measuring the amount of a substance.

Avogadro’s Number

Avogadro’s number is 6.02 x 10^23, representing the number of particles in one mole of a substance.

Molar Mass

Molar mass is the mass of one mole of a specific element or compound.

Avogadro’s Hypothesis

Avogadro’s hypothesis states that equal volumes of gases at the same temperature and pressure contain an equal number of particles.

Percent Composition

Percent composition is the relative amounts of elements present in a compound.

Empirical Formula

The empirical formula is the lowest whole-number ratio of atoms or molecules in a compound.

Molecular Formula

The molecular formula is the experimentally determined formula, usually a simple whole-number multiple of the empirical formula.

Diatomic Molecules

Diatomic molecules include Br2, I2, N2, Cl2, H2, O2, and F2.

Density

Density (D) is calculated as mass (M) divided by volume (V), D = M/V.

Reactants

Reactants are the substances you start with in a chemical reaction.

Ideal Gases

Hypothetical gases that don't exist in reality due to assumptions like no molecular volume and no intermolecular forces.

Gas Variables

Pressure (P), Volume (V), Temperature (T), and Amount (n) are the four key properties that describe a gas.

Boyle's Law

States that the pressure and volume of a gas are inversely proportional when temperature is constant (P1V1 = P2V2).

Charles's Law

Describes the direct relationship between volume and temperature of a gas at constant pressure (V1/T1 = V2/T2).

Gay-Lussac's Law

Shows the direct relationship between pressure and temperature of a gas at constant volume (P1/T1 = P2/T2).

Combined Gas Law

Combines Boyle's, Charles's, and Gay-Lussac's laws into a single equation (P1V1/T1 = P2V2/T2).

Ideal Gas Law

Relates the pressure, volume, amount, and temperature of a gas using the constant R (PV = nRT).

Dalton's Law of Partial Pressure

States that the total pressure of a gas mixture is the sum of the partial pressures of each gas.

Graham's Law

Describes the relationship between the rates of diffusion or effusion of two gases based on their molar masses.

Thermochemistry

The study of energy changes during chemical reactions and changes in the state of matter.

STP

Standard temperature and pressure; 0°C and 1 atm pressure (101.3 kPa)

Solution

A homogeneous mixture that is mixed molecule by molecule

Solvent

The dissolving medium

Solute

The dissolving particles

Aqueous solution

A solution with water as the solvent

Saturated solution

Contains the maximum amount of solute dissolved

Unsaturated solution

Can still dissolve more solute

Supersaturated solution

A solution holding more solute than theoretically possible

Miscible

Two liquids that can dissolve each other

Immiscible

Two liquids that don’t mix or dissolve together

Concentrated solution

Has a large amount of solute

Dilute solution

Has a small amount of solute

Stock solution

Pre-made solutions with known molarities

Colloid

A mixture with particles ranging between 1 and 1000 nanometers in diameter

Electrolytes

Compounds that conduct an electric current in aqueous solutions

Vapor pressure

Lowered in solutions

Boiling point elevation

Occurs in solutions

Freezing point depression

Occurs in solutions

Henry’s Law

S1/P1 = S2/P2, where S is solubility and P is pressure

Dilution

MIVI = MFVF, where M is molarity, V is volume, I is initial, and F is final