Explain Avogadro's law using the kinetic–molecular theory of gases.

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1. Avogadro's law states that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules.
2. The kinetic-molecular theory of gases provides a framework to understand this law by describing gases as composed of a large number of small particles (molecules) in constant, random motion.
3. According to the kinetic-molecular theory, the volume of a gas is determined by the space in which the gas molecules move, not by the size of the molecules themselves, which are considered negligible.
4. When the temperature and pressure are constant, the average kinetic energy of the gas molecules remains the same, meaning that the number of molecules is directly proportional to the volume of the gas.
5. Thus, Avogadro's law can be explained by the kinetic-molecular theory as the result of the constant motion and negligible size of gas molecules, leading to a direct relationship between the number of molecules and the volume of the gas.

Key Concepts

Avogadro's Law

Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules. This principle highlights the direct relationship between the volume of a gas and the number of moles, implying that if the amount of gas increases, the volume must also increase, provided temperature and pressure remain constant.

Kinetic-Molecular Theory

The Kinetic-Molecular Theory explains the behavior of gases in terms of particles in constant motion. It posits that gas molecules are in rapid, random motion and that their collisions with each other and the walls of their container result in pressure. This theory helps to understand how changes in temperature and volume affect gas behavior, supporting Avogadro's Law.

Molar Volume

Molar volume is the volume occupied by one mole of a substance at standard temperature and pressure (STP), which is approximately 22.4 liters for an ideal gas. This concept is crucial for understanding Avogadro's Law, as it provides a quantitative measure that relates the number of gas molecules to the volume they occupy, reinforcing the idea that volume is directly proportional to the number of moles.