Chemistry Block 1A Comprehensive Vocabulary

Vocabulary flashcards covering states of matter, gas laws, phase changes, chemical classification, reaction energetics, and atomic structure definitions.

Matter

Anything that occupies space and has mass.

Physical Change

The conversion of a substance from one state of matter to another without changing its chemical composition.

Condensed Phases

A collective term referring to liquids and solids because their constituent particles are very close together compared to gases.

Kinetic Molecular Theory (KMT) of Gases

A model that describes the behavior of ideal gases at the particle level, providing a microscopic explanation for macroscopic gas properties.

Elastic Collision

A collision in which no kinetic energy is lost, but is merely transferred between colliding particles or container walls.

Ideal Gas

A theoretical gas model whose particles have negligible volume and exert no attractive or repulsive interparticle forces on one another.

Boyle's Law

States that for a fixed amount of gas at constant temperature, the gas volume is inversely proportional to its pressure ($P_1 V_1 = P_2 V_2$).

Charles' Law

States that for a fixed amount of gas at constant pressure, the volume is directly proportional to its absolute temperature ($\frac{V_1}{T_1} = \frac{V_2}{T_2}$).

Gay-Lussac's (Jolly) Law

States that for a fixed amount of gas at constant volume, the pressure is directly proportional to its absolute temperature ($\frac{P_1}{T_1} = \frac{P_2}{T_2}$).

Avogadro's Law

States that for a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas particles ($\frac{V_1}{n_1} = \frac{V_2}{n_2}$).

Ideal Gas Law

The unifying gas equation $PV = nRT$ combining Boyle's, Charles', and Avogadro's laws, where $R$ represents the ideal gas constant.

Isothermal Process

A change during which the temperature of the substance remains constant because energy is exclusively used to alter the state or phase rather than the kinetic energy of the particles.

Melting (Fusion)

An endothermic process in which a solid transforms into a liquid by absorbing enthalpy of fusion ($\Delta H_{fus}$).

Solidification (Freezing)

An exothermic process in which a liquid transforms into a solid, releasing energy equal to $-\Delta H_{fus}$.

Boiling (Vaporization)

An endothermic phase transition where a liquid transforms into a gas at its boiling point, requiring enthalpy of vaporization ($\Delta H_{vap}$).

Condensation

An exothermic process in which a gas transforms into a liquid, releasing energy equal to $-\Delta H_{vap}$.

Sublimation

An endothermic and isothermal phase transition where a solid transforms directly into a gas without passing through the liquid phase.

Deposition

An exothermic phase change in which a gas transforms directly into a solid without passing through the liquid phase.

Enthalpy of Sublimation

The energy change for a solid-to-gas phase transition, calculated using the equation $\Delta H_{sub} = \Delta H_{fus} + \Delta H_{vap}$.

Pure Substance

Matter characterized by a uniform and unchanging composition and constant physical properties, which cannot be separated into simpler substances by physical means.

Element

The simplest form of a pure substance that cannot be broken down into simpler substances by ordinary chemical reactions.

Compound

A pure substance formed when two or more different elements are chemically combined in a fixed, definite ratio by mass.

Mixture

A physical combination of two or more elements and/or compounds that retain their individual properties and can be separated by physical means.

Homogeneous Mixture

A mixture with a consistent and uniform distribution of components throughout, appearing as a single phase.

Heterogeneous Mixture

A mixture with a non-uniform distribution of components, exhibiting varying compositions and distinct, visible phases.

Kinetic Energy

The energy of motion associated with particle movement in chemistry, calculated using the formula $KE = \frac{1}{2} m v^2$.

Potential Energy

Stored energy resulting from an object's position, arrangement, chemical bonds, or electrostatic forces between particles.

Exothermic Reaction

A chemical reaction that converts chemical potential energy into kinetic energy (heat), releasing heat to its surroundings.

Endothermic Reaction

A chemical reaction that absorbs kinetic energy (heat) from its surroundings and converts it into chemical potential energy.

Activation Energy

The minimum potential energy required for a chemical reaction to occur, functioning as an energy barrier that reactants must overcome.

Atomic Mass Unit (amu)

A unit of mass defined as exactly $\frac{1}{12}$ the mass of a carbon-12 atom, where $1\,amu = 1.6605 \times 10^{-24}\,g$.

Fundamental Charge (e)

The physical constant representing the magnitude of an electron's charge, equal to $1.602 \times 10^{-19}\,C$.