Semester 2 Final Study Guide Vocabulary

Flashcards for vocabulary terms in the Semester 2 Final Study Guide.

Significant Figures

Digits in a measurement that are known with certainty plus one final digit that is estimated.

Isotope

Atoms of the same element with different numbers of neutrons.

Ion

An atom or molecule with a net electric charge due to the loss or gain of electrons.

Atomic Mass

The mass of an atom, typically expressed in atomic mass units (amu).

Absolute Mass

The actual mass of a single atom in grams.

Formula Mass

The sum of the atomic masses of all atoms in a chemical formula.

Polarity

A molecule with a partially positive end and a partially negative end due to unequal sharing of electrons.

Intermolecular Forces

Attractive or repulsive forces between molecules.

Mole

The SI unit of amount of substance, equal to the number of atoms in 12 grams of carbon-12 (approximately 6.022 x 10^23).

Molar Mass

The mass of one mole of a substance, typically expressed in grams per mole (g/mol).

Percent Composition

The percentage by mass of each element in a compound.

Empirical Formula

The simplest whole-number ratio of atoms in a compound.

Molecular Formula

The actual number of atoms of each element in a molecule.

Limiting Reactant

The reactant that is completely consumed in a chemical reaction and limits the amount of product that can be formed.

Excess Reactant

The reactant that is present in a greater amount than necessary to react completely with the limiting reactant.

Stoichiometry

The study of quantitative relationships between reactants and products in chemical reactions.

Hydrate

A compound that contains water molecules within its crystal structure.

Precipitate

A solid that forms from a solution during a chemical reaction.

Double Replacement Reaction

A reaction in which ions are exchanged between two reactants.

Single Displacement Reaction

A reaction in which one element replaces another in a compound.

Synthesis Reaction

A reaction in which two or more reactants combine to form a single product.

Decomposition Reaction

A reaction in which a single reactant breaks down into two or more products.

Solute

The substance that is dissolved in a solution.

Solvent

The substance that dissolves the solute in a solution.

Solution

A homogeneous mixture of two or more substances.

Electrolyte

A substance that conducts electricity when dissolved in water.

Molarity

The number of moles of solute per liter of solution.

Dissociation

The process by which a compound separates into ions when dissolved in a solvent.

Solubility

The maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature.

Saturated Solution

A solution that contains the maximum amount of dissolved solute.

Unsaturated Solution

A solution that contains less than the maximum amount of dissolved solute.

Supersaturated Solution

A solution that contains more than the maximum amount of dissolved solute.

Dilute Solution

A solution that contains a small amount of solute.

Concentrated Solution

A solution that contains a large amount of solute.

Solubility Curve

A graph showing the solubility of a substance as a function of temperature.

Colligative Properties

Properties of solutions that depend on the concentration of solute particles, but not on the nature of the solute.

Dissolution

The process of dissolving a solute in a solvent.

Kinetic Molecular Theory

A theory explaining the behavior of gases based on the motion of their particles.

Ideal Gas

A hypothetical gas that obeys the ideal gas law exactly.

Real Gas

A gas that does not obey the ideal gas law exactly.

STP

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

Pressure

The force exerted per unit area.

Density

Mass per unit volume.

Vapor Pressure

The pressure exerted by a vapor in equilibrium with its liquid or solid phase.

Collision Theory

The theory that chemical reactions occur when molecules collide with sufficient energy and proper orientation.

Effective Collision

A collision that results in a chemical reaction.

Activation Energy

The minimum energy required for a reaction to occur.

Activated Complex

A temporary, unstable arrangement of atoms formed during a reaction.

Enthalpy (ΔH)

The heat content of a system at constant pressure.

Entropy (ΔS)

A measure of the disorder or randomness of a system.

Catalyst

A substance that speeds up a reaction without being consumed in the reaction.

Endothermic

A process that absorbs heat (positive ΔH).

Exothermic

A process that releases heat (negative ΔH).

Acid

A substance that donates protons or accepts electrons.

Base

A substance that accepts protons or donates electrons.

pH

A measure of the acidity or basicity of a solution.

Hydronium Ion (H3O⁺)

A water molecule that has accepted a proton.

Hydroxide Ion (OH⁻)

A negatively charged ion consisting of oxygen and hydrogen.

Arrhenius Acid

A substance that produces H+ ions in water.

Arrhenius Base

A substance that produces OH- ions in water.

Bronsted-Lowry Acid

A proton donor.

Bronsted-Lowry Base

A proton acceptor.

Neutralization

The reaction between an acid and a base.

Diprotic Acid

An acid that can donate two protons per molecule.

Logarithmic Scale

A scale in which each unit represents a tenfold increase.

Indicator

A substance that changes color in response to a change in pH.