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Chemistry LibreTexts

2: The States of Matter

  • Page ID
    221445
    • 2.1: States of Matter
      Another way that we can describe the properties of matter is the state (also called phase). The amount of energy in molecules of matter determines the state of matter. Matter can exist in one of several different states, including a gas, liquid, or solid state.
    • 2.2: Kinetic-Molecular Theory
      The kinetic-molecular theory is a theory that explains the states of matter and is based on the idea that matter is composed of tiny particles that are always in motion. The theory helps explain observable properties and behaviors of solids, liquids, and gases. However, the theory is most easily understood as it applies to gases. The theory applies specifically to a model of a gas called an ideal gas.
    • 2.3: Gas Laws
      The physical properties of gases are predictable using mathematical formulas known as gas laws.
    • 2.4: Diffusion and Effusion- Graham's Law
    • 2.5: Changes in State and Heating Curves
      Fusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes. Changes of state are examples of phase changes, or phase transitions. All phase changes are accompanied by changes in the energy of a system. Changes from a more-ordered state to a less-ordered state (such as a liquid to a gas) are endothermic. Changes from a less-ordered state to a more-ordered state (such as a liquid to a solid) are always exothermic.

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