📚 B.3 Gas Laws | B.3 气体定律
Gas laws describe how the pressure, volume, and temperature of an ideal gas are interrelated. These macroscopic relationships form the foundation of thermal physics and can be explained by the microscopic kinetic theory of gases. Understanding these laws is essential for IB Physics students to tackle problems involving changes of state, thermodynamic processes, and the behaviour of gases at the molecular level.
气体定律描述了理想气体的压强、体积和温度之间的相互关系。这些宏观关系构成了热物理学的基础，并可以通过微观的气体分子动理论加以解释。理解这些定律对于 IB 物理学生解决涉及状态变化、热力学过程以及分子层面气体行为的问题至关重要。
1. Macroscopic Variables: Pressure, Volume, and Temperature | 宏观变量：压强、体积和温度
The state of a fixed mass of gas is determined by three macroscopic quantities: pressure p, volume V, and thermodynamic temperature T. Pressure is defined as the force per unit area exerted by the gas on the walls of its container, measured in pascals (Pa). Volume is the space occupied by the gas, usually expressed in cubic metres (m³). Temperature must be measured on the kelvin scale (K), which is an absolute scale where 0 K corresponds to the minimum possible internal energy.
一定质量气体的状态由三个宏观量决定：压强 p、体积 V 和热力学温度 T。压强定义为单位面积上气体对容器壁施加的力，单位为帕斯卡（Pa）。体积是气体占据的空间，通常用立方米（m³）表示。温度必须用开尔文（K）温标测量，这是一种绝对温标，0 K 对应可能的最小内能。
us scale by T(K) = θ(°C) + 273.15, and all gas law calculations require the use of kelvin.
压强通常表示为 p = F/A。在气体定律中，我们将 p、V 和 T 视为确定气体样本条件的状态变量。开尔文温度与摄氏温标的关系为 T(K) = θ(°C) + 273.15，所有气体定律的计算都需要使用开尔文温度。
2. Boyle’s Law | 玻意耳定律
rature, the pressure p is inversely proportional to the volume V. This can be written as p ∝ changes from state 1 to state 2 while the temperature remains the same, then p₁V₁ = p₂V₂.
玻意耳定律指出，对于一定质量的气体，在温度不变的条件下，压强 p 与体积 V 成反比。可写为 p ∝ 1/V，或 pV = 常数。如果气体在温度不变的情况下从状态 1 变化到状态 2，则有 p₁V₁ = p₂V₂。
Experimentally, a graph of p against V yields a hyperbola, while a graph of p against 1/V gives a straight line passing through the origin. This linear relationship provides a simple test for an ideal gas obeying Boyle’s law.
在实验上，p 对 V 的图线是双曲线，而 p 对 1/V 的图线是一条通过原点的直线。这种线性关系为检验理想气体是否遵守玻意耳定律提供了简单方法。
3. Charles’s Law | 查理定律
Charles’s law describes
Published by TutorHao | IB Physics Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图