Matter: States & Changes Flashcards

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Matter

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Matter is anything that has mass and occupies space. It exists in discrete forms (solid, liquid, gas) and can be described by properties that are either extensive or intensive. It is the basic stuff that makes up the universe.

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Mass

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Mass is the amount of matter in an object. It is a common extensive property measured in kilograms (kg) and does not depend on the object's shape. Mass is related to weight but is not the same thing in all contexts.

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Volume

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Volume is the space that matter occupies. It is an extensive property and can be measured in liters (L) or cubic meters (m^3). It helps determine density when combined with mass.

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Density

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Density is mass per unit volume, defined as $\\rho = \\frac{m}{V}$ in appropriate units like $kg/m^3$. It is an intensive property, meaning it does not depend on how much matter you have. High density means matter is more tightly packed.

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Atom

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An atom is the smallest unit of an element that retains the properties of that element. Atoms can combine with other atoms to form molecules, the building blocks of compounds and mixtures.

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Molecule

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A molecule is a group of two or more atoms chemically bonded together. Molecules are the smallest unit of a compound that retains its chemical properties.

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Element

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An element is a pure substance consisting of a single type of atom. Elements cannot be broken down into simpler substances by chemical means under normal conditions.

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Compound

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A compound is a pure substance formed when two or more elements combine chemically in fixed proportions. Compounds have properties different from the elements that compose them.

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Mixture

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A mixture contains two or more substances that are physically blended and can be separated by physical methods. The substances retain their own identities.

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Pure substance

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A pure substance has a fixed composition and distinct properties. It can be either an element or a compound, and its composition does not vary.

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Physical property

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A physical property describes matter without changing its identity, such as color, density, or melting point. These can be observed or measured without a chemical reaction.

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Chemical property

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A chemical property describes how a substance reacts with other substances, such as flammability or reactivity. Observing these requires a chemical change.

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Phase change

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A phase change is a physical change from one state of matter to another (solid, liquid, gas). Energy is often involved, but the chemical identity stays the same.

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Melting

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Melting is the phase change from solid to liquid, with energy absorbed by the substance. The solid gains enough energy to overcome rigid structure and flow becomes liquid.

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Vaporization

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Vaporization is the phase change from liquid to gas, which can occur by evaporation or boiling. It requires energy input and does not change chemical identity.

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Condensation

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Condensation is the phase change from gas to liquid, releasing energy as particles come closer together. The substance remains chemically the same.

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Sublimation

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Sublimation is the phase change from solid to gas, typically with energy absorption. No liquid phase forms in between.

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Deposition

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Deposition is the phase change from gas to solid, releasing energy as particles settle into a solid lattice without becoming a liquid first.

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Evidence of chemical change

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Evidence includes formation of a new substance with different properties, color change, odor change, gas production, precipitate formation, or energy release/absorption.

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Kinetic theory

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The kinetic theory explains matter in terms of particle energy and motion. Higher energy leads to higher temperatures and different states (solid, liquid, gas).