Effects of Change of Pressure

When we look around us, we notice a wide range of objects in all shapes, sizes, and textures. Everything is made up of a material called matter. From the air, we breathe to the food we eat, and even a single drop of water is all matters. As we glance around, we can see that all of the items stated above take up space and have mass. They have both mass and volume, in other words. Solid, liquid, and gaseous phases of matter are the three basic types of matter. To comprehend the impact of pressure on the three states of matter, we must first comprehend their fundamental qualities.

What is a Solid-state?

The solid state is one of the states of matter. There are three states of matter: solid, liquid, and gas. However, as we proceed through the grades, the concepts become more advanced, and there are more things to learn. Solids have characteristics that set them apart from liquids and gases. They can withstand any force that is applied to their surface. The solid state of a compound, on the other hand, is mostly determined by the properties of atoms, such as their organisation and the forces that exist between them.

Physical and Chemical Properties of Solids

1. Solids are incompressible, which means that the constituent particles are grouped close together and that there is very little space between them.
2. Solids are rigid as there isn’t enough space between the constituent particles, causing it to be hard or fixed.
3. Because of their fixed mass, volume, and shape, solids have a compact arrangement of constituent particles.
4. Molecules have a short intermolecular distance. As a result of this, the force between the constituent particles (atoms, molecules, or ions) is extraordinarily strong.
5. Only the particles that make up the components can fluctuate around their mean location.

Liquid state

A liquid is a nearly incompressible fluid that adapts to the shape of its container while retaining a (nearly) constant volume at any pressure. 

If the temperature and pressure are constant, the volume is fixed. When a solid is heated past its melting point and the pressure exceeds the triple point of the substance, it becomes liquid. Despite the existence of intermolecular (or interatomic or interionic) interactions, the molecules have sufficient energy to move about, and the structure is mobile. This means that a liquid’s shape is dictated by its container, not the liquid itself. Water is the most well-known exception, as its volume is often greater than that of the analogous solid. A liquid’s critical temperature is the highest temperature at which it can survive. A transition between solid and gaseous phases is the liquid state of matter. Water exists in three states: ice (solid), liquid (water), and gas (vapour).

Gaseous State

Gas refers to a substance that can be compressed. Not only will gas conform to the shape of the container in which it is contained, but it will also expand to fill it. Intermolecular forces have a modest influence (or none at all in an ideal gas) because the molecules in a gas have ample kinetic energy, and the average distance between neighbouring molecules is much bigger than the molecular dimension. A gas has no definite shape or length, but it fills the whole volume of the container it is kept in. A liquid can be turned into a gas by either heating it to the boiling point under constant pressure or reducing the pressure under constant temperature. 

A vapour is a gas that can be liquefied solely by compression at temperatures below its critical temperature without cooling. When a liquid (or solid) and a vapour are in equilibrium, the gas pressure equals the liquid’s vapour pressure (or solid).

Effect of Pressure on states of Matter

As solids and liquids are non-compressible states of matter, pressure has no effect on them. When pressure is applied to a solid, however, it breaks. On the other hand, applying pressure at a low temperature might cause gases to liquefy. For example, you may have witnessed smoke spreading all around the stage during parties or stage concerts. Dry ice is all there is to it (solid carbon dioxide). Solid carbon dioxide is held at high pressure and instantaneously liquefies when the pressure is dropped to 1 atmosphere.

The space between the particles that make up a substance is what determines its state of matter. As a result, when pressure is given to a gas, it compresses into a liquid, and when pressure is applied to a liquid, it solidifies. Pressure has a negligible influence on solids. When pressure is applied to a substance, the state of the substance changes from:

Gas → Liquid → Solid

Other effect of change of Pressure

The physical condition of matter can also be altered by varying the pressure applied to it. By applying pressure and lowering the temperature, gases can be liquefied. A gas is compressed when high pressure is applied to it, and when the temperature is lowered, it is converted to a liquid. As a result, we can say that gases can be compressed and cooled into liquids.

Examples of Change in Pressure

Under normal temperature and pressure circumstances, carbon dioxide is a gas. By applying pressure at room temperature, it can be liquefied. Under high pressure, solid carbon dioxide (CO₂) is stored. When the pressure is reduced to 1 atmosphere, solid CO₂ is transformed directly to a gaseous state, bypassing the liquid state. This is why solid carbon dioxide is also referred to as dry ice.

Sample Questions

Question 1: What are the physical and chemical properties of solids?

Answer:

1. Solids are incompressible, which means that the constituent particles are grouped close together and that there is very little space between them.
2. Solids are rigid as there isn’t enough space between the constituent particles, causing it to be hard or fixed.
3. Because of their fixed mass, volume, and shape, solids have a compact arrangement of constituent particles.
4. Molecules have a short intermolecular distance. As a result of this, the force between the constituent particles (atoms, molecules, or ions) is extraordinarily strong.
5. Only the particles that make up the components can fluctuate around their mean location.

Question 2: What is the expansion in physics?

Answer:

Physics is a branch of natural science that studies the nature and properties of matter and energy. Physicists might use either a theoretical or an experimental approach to address their questions.

Expansion occurs when the volume of a solid substance grows without the mass rising. The density of the substance of the drug is reduced as a result. Expansion occurs when the kinetic energy of the solid particles increases as a result of heating.

Question 3: Why do naphthalene balls disappear with time without leaving any solid behind?

Answer:

Naphthalene undergoes sublimation easily i.e., the change of state of naphthalene from solid to gas without the intervention of the liquid state. Thus, naphthalene balls keep on forming naphthalene vapours which disappear into the air with time without leaving any solid.

Question 4: What would be the effect on gas molecules if:

(a) pressure is increased and

(b) pressure is decreased?

Answer:

(a) If pressure is increased, it will produce fewer gas molecules.

(b) If pressure is decreased, it will produce more gas molecules.

Question 5: Why is ammonia stored in storage tanks?

Answer:

The ammonia in storage tank accomplishes two goals. First, it stores ammonia at high pressure to prevent the reverse reaction, which would result in less ammonia and more nitrogen and hydrogen. Second, it conveys a significant message. Methamphetamine, a hazardous substance of abuse, is made from ammonia. Locks and other safety features put inside the tanks assist prevent ammonia theft for use in illegal activities.

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