Why do liquids have a fixed volume but not a fixed shape and what happens to the density and temperature of a gas as it expands?
Liquids display strong intermolecular forces of attraction in order to keep the molecules together. However, these forces are not strong enough to hold them into definite positions, as in a solid crystalline lattice.
When a gas expands, its density decreases. This is because the same amount of gas is now occupying a larger volume, which means that the molecules are more spread out. As a result, the number of molecules per unit volume decreases, leading to a decrease in density.
The temperature of a gas can vary when it expands, depending on the conditions under which the expansion occurs. If the expansion is carried out slowly enough so that heat can flow into or out of the gas, then the temperature will remain constant. This is known as an isothermal expansion. However, if the expansion is carried out quickly enough so that there is no time for heat to flow into or out of the gas, then the temperature will decrease. This is known as an adiabatic expansion.
In summary, when a gas expands, its density decreases and its temperature may either remain constant (in an isothermal expansion) or decrease (in an adiabatic expansion).
Liquids occupy a fixed volume but no fixed shape. This is because the particles in the liquid state are not packed closely and also arranged disorderly. There are spaces between the particles, which are the particles are bound by loose intra-molecular forces of attraction. In a liquid, the particles are still in close contact, so liquids have a definite volume. However, because the particles can move about each other rather freely, a liquid has no definite shape and takes a shape dictated by its container. Due to the weak intern clear force of attraction, the gaseous particles have enough kinetic energy and they can move in any direction without any restrictions. Hence, the gases do not have a fixed shape and fixed volume.Because the particles in liquids are very close together liquids do not easily compress, so their volume is fixed. Liquids have a fixed volume but they do not have a fixed shape. Liquids, on the other hand, are the only substances with no definite shape but a fixed volume. Liquids do not have a fixed shape but they do have a fixed volume. The particles are very close together. Most of the particles touch each other. The particles can move around. There is a decrease in density of a gas when increase in the temperature because the intermolecular space between the gas molecules is increased as a result volume increases and density decreases.A gas does not have a fixed shape or fixed volume due to following reason: The internuclear force of attraction between the gaseous particles is very less as compared to solids and liquids. When gas expands, the decrease in pressure causes the molecules to slow down. This makes the gas cold. When a liquid or gas is heated, the molecules move faster, bump into each other, and spread apart. Because the molecules are spread apart, they take up more space. They are less dense. While compressing the gas adiabatically, the gas temperature increases, increasing the gas pressure. There is a decrease in density of a gas when increase in the temperature because the intermolecular space between the gas molecules is increased as a result volume increases and density decreases.Liquids have a definite volume but no definite shape. The interparticle force of liquids is lesser than that of solids, and thus, liquids can flow easily and take the shape of a container. The liquids continue to flow unless they are held in a container. Hence, they don't have a definite shape. In a liquid, the particles are still in close contact, so liquids have a definite volume. However, because the particles can move about each other rather freely, a liquid has no definite shape and takes a shape dictated by its container. Liquids, on the other hand, are the only substances with no definite shape but a fixed volume. On the base of molecular interactions and particle arrangement, there are three states of matter: solid, liquid, and gas.
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