Key Concepts in Chemistry

This collection of flashcards covers essential vocabulary and concepts from the lecture notes on chemistry, including definitions and comparisons of key terms.

Scientific Method

A systematic approach to inquiry that includes observation, hypothesis formulation, experimentation, and conclusion.

Theory vs. Law

A theory explains why phenomena occur, while a law describes the relationship between variables.

Macroscopic Domain

Refers to the bulk properties of matter visible to the naked eye.

Microscopic Domain

Refers to the properties of matter on the atomic or molecular level that are not visible directly.

Symbolic Domain

The use of chemical symbols and equations to represent chemical substances and reactions.

States of Matter

The distinct forms that different phases of matter take on: solid, liquid, gas, and plasma.

Mass vs. Weight

Mass is a measure of the amount of matter in an object, while weight is the force of gravity acting on that mass.

Law of Conservation of Mass

Mass is neither created nor destroyed in a chemical reaction.

Elements vs. Compounds

Elements are pure substances consisting of one type of atom, while compounds consist of two or more different types of atoms chemically bonded.

Pure Substance vs. Mixture

A pure substance contains only one type of material, while a mixture contains two or more different substances that retain their individual properties.

Physical Change vs. Chemical Change

A physical change alters the form of a substance but not its identity, while a chemical change alters the substance's chemical structure.

Homogeneous Mixture

A mixture that has a uniform composition throughout, also known as a solution.

Heterogeneous Mixture

A mixture that consists of visibly different substances or phases.

Extensive Properties

Properties that depend on the amount of matter present, such as mass and volume.

Intensive Properties

Properties that do not depend on the amount of matter present, such as density and boiling point.

Significant Figures

Digits in a number that carry meaningful information about its precision.

Scientific Notation

A mathematical expression used to represent numbers as a product of a coefficient and a power of ten.

Atomic Theory

The theory that matter is composed of discrete units called atoms.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Cation vs. Anion

Cations are positively charged ions, while anions are negatively charged ions.

Molar Mass

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

Empirical Formula

A chemical formula that shows the simplest whole number ratio of elements in a compound.

Molarity

A measure of concentration that expresses the number of moles of solute per liter of solution.

Redox Reaction

A reaction that involves the transfer of electrons between two substances.

Calorimetry

The science of measuring the heat of chemical reactions or physical changes.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions, typically between a metal and a nonmetal.

Covalent Bond

A chemical bond formed by the sharing of electron pairs between atoms, typically between two nonmetals.

Mole Concept

A unit of measurement in chemistry representing 6.022 \times 10^{23} particles (atoms, molecules, ions, etc.) of a substance, also known as Avogadro's number.

Balancing Chemical Equations

The process of ensuring that the number of atoms of each element is the same on both the reactant and product sides of a chemical equation, in accordance with the Law of Conservation of Mass.

Formal Charge

The hypothetical charge an atom would have if all electrons in bonds were shared equally between atoms.