气体液化
建议主题——气体液化
物质被定义为任何占据空间并具有质量的东西。现代科学家将物质分为两类：物理性质和化学性质。该物质根据其物理性质分为固体、液体或气体。固体包括糖、沙子、铁和岩石等物质。水、牛奶、汽油、油等是液体，而空气、氧气和蒸汽是气体。通过改变压力和温度，一种物质状态可以转变为另一种状态。施加压力并降低温度可以将气体变成液体。这将在下面进一步深入介绍。
什么是气体？
所有物质都可以根据其物理状态分为三种类型：固体、液体和气体。常见的气体包括空气、氧气、氢气、氮气、二氧化碳等。与固体和液体相比，气体中颗粒之间的距离要大得多。
A gas has relatively big gaps between its particles. The attraction between the particles in a gas is extremely weak. As a result, gas particles are free to flow in any direction. The positions of gas particles, as well as the distances between them, are not fixed.
气体的粒子具有最高的动能。结果，气体具有最无组织的粒子排列。由于巨大的动能和低吸引力，气体粒子以极快的速度向各个方向移动。当快速移动的气体粒子与容器壁碰撞时，粒子会施加气体压力。结果，气体对容器壁施加压力。当将气体放入空容器中时，它会迅速扩散到容器中并完全充满容器。当气体被加热时，气体的粒子开始移动得越来越快。
气体的一些特性是。
- 气体的形状不固定。
- 气体没有固定的体积。
- 由于它的颗粒相距很远，并且它们之间有很大的间隙，所以气体很容易被压缩。
- 由于气体中的粒子相距很远，因此它的密度极低。
- 气体完全充满其容器，因为它的粒子由于高动能和低吸引力而在各个方向上快速移动。
- 气体自由流动是因为它的粒子在其运动中不受限制。
改变压力也可以改变物质的物理状态。换句话说，物质的物理状态可以通过增加或降低压力来改变。例如，可以通过在降低温度的同时增加压力来将气体转化为液体。当压力降低时，一些固体，如固体二氧化碳，可以转化为气体。
气体液化——通过施加压力和降低温度
The process of liquefaction of gases is the transformation of substances from their gaseous state to their liquid state. Gases are a type of substance in which particles are often very far apart, move very quickly, and do not have strong attraction forces between them. Within the particles, there is a lot of empty space, and these particles have a lot of kinetic energy. Particles in liquids, on the other hand, are confined by fairly strong forces of attraction, and their kinetic energy is lower than that of gaseous particles.
当对气体施加高压时，气体会被压缩成很小的体积，而当温度降低时，它会液化。因此，我们可能会争辩说，气体可以通过压缩和冷却被液化并转化为液体。这以下列方式发生。
气体变成液体
- 气体在其粒子之间有很大的空间。通过将气体限制在气缸中并用活塞对其进行压缩，我们可以最小化其粒子之间的空间或距离。
- 如果对活塞施加足够的力或压力，气体会被高度压缩成小体积。气体粒子变得如此接近，以至于它们开始相互吸引，足以形成液体，据说气体已经液化。当气体被过度压缩时，压缩会产生热量。
- 因此，需要在施加压力的同时冷却气体以使其液化，以去除压缩过程中产生的热量。冷却有助于通过降低压缩气体的温度来液化压缩气体。因此，可以推断出施加压力和降低温度可以使气体液化。
- 换句话说，气体可以通过压缩和冷却来液化。在可能发生压力液化之前，气体必须冷却到特定温度以下。
- 通常将水倒在输送压缩气体的线圈上以保持冷却。通过施加高压和降低温度，可以将氨气液化。即，可以将压缩和冷却的氨气液化。因此，可以通过增加压力和降低温度来实现物质从气体到液体的状态变化。
- 因此，增加压力和降低温度可以使气体液化。当对气态粒子施加压力时，它们会聚集在一起并开始相互吸引。
- 当气体的压力增加时，它的分子会变得更紧密，它的温度会下降，从而消除足够的能量使其从气态转变为液态。当气体暴露在高压和低温下时，它会液化。必须施加的压力和温度由气体分子的分子力决定。
Solid being converted into Gas
- Changing the state of matter from a gas to a liquid can be accomplished by increasing pressure and reducing temperature. Even changing the state of matter by lowering the pressure and rising the temperature is possible. Take, for example, the storage of solid carbon dioxide or dry ice under high pressure.
- This is due to the fact that when the pressure on solid carbon dioxide is reduced, it is instantly transformed into carbon dioxide gas. When a slab of solid carbon dioxide is exposed to air, the pressure on it is decreased to normal atmospheric pressure, the temperature rises, and the carbon dioxide gas begins to form.
- As a result, the transformation of solid carbon dioxide into carbon dioxide gas is a shift in the state from solid to gas, which is initiated by a drop in air pressure and a rise in atmospheric temperature. Solid carbon dioxide is a type of dry ice that is white in colour. Carbon dioxide in solid form is a very chilly substance. It’s used to keep ice cream cool and to deep freeze meals. Dry ice is defined as solid carbon dioxide that converts directly to carbon dioxide gas rather than melting to generate liquid-like ordinary ice.
示例问题
问题1：为什么气体没有固定的形状和体积？
回答：
Since the positions of its particles are not fixed, gases do not have a fixed shape, and gases do not have a fixed volume because the spaces between its particles are not fixed.
问题2：当气体被加热时，会发生什么？
回答：
When a gas is heated, the gas particles begin to move more quickly.
问题3：为什么气体会对容器壁施加压力？
回答：
The pressure exerted by a gas is caused by collisions of fast-moving gas particles with the container’s walls.
问题 4：为什么干冰在冷却方面比普通冰更有效？
回答：
Dry ice can produce temperatures that are substantially lower than ordinary ice. As a result, it is far more effective at cooling than ordinary ice.
问题5：在液态和气态中，粒子是如何排列的？
回答：
In the liquid state, particle arrangement is less organised, and in the gaseous state, particle arrangement is non-existent.