Question

Which one of the following statements is not correct about the three states of matter, i.c., solid, liquid and gascous (1) Molecules of a solid possess least energy , where as those of a gas possess high energy (2) The density of solid is highest, where as that of gases is lowest (3) Gases like liquids possess definite volume (4) Moleculcs of a solid possess vibratory motion

Short answer

Statement (3) is not correct. Gases do not have a definite volume; they expand to fill any container.

Step-by-step solution

Analyze the energy possession statement

Evaluate statement (1). In this statement, it is claimed that molecules of a solid possess the least energy, whereas those of a gas possess high energy. This statement is correct as molecules in solids have limited movement and hence lower energy compared to gases where molecules move freely and energetically.

Analyze the density statement

Evaluate statement (2). This statement claims that the density of solid is the highest, whereas that of gases is the lowest. This statement is correct since solids have tightly packed molecules compared to gases which have widely spaced molecules.

Analyze the volume statement

Evaluate statement (3). It states that gases, like liquids, possess definite volume. This statement is incorrect because gases do not have a definite volume; they expand to fill any container they are in, unlike liquids which have a definite volume but take the shape of their container.

Analyze the motion in solids statement

Evaluate statement (4). This statement claims that molecules of a solid possess vibratory motion. This statement is correct as molecules in solids are fixed in place but can vibrate around their fixed positions.

Key concepts

Molecular Energy

In different states of matter, the energy that molecules possess varies significantly.
In solids, molecules have the least amount of energy because they are tightly packed and cannot move freely.
They can only vibrate around their fixed positions.
On the other hand, in liquids, molecules have more energy than in solids and can move around more freely, although still being attracted to each other.
In gases, molecules have the highest energy.
This is because they are far apart and move freely at high speeds.
This variation in energy levels is crucial in defining the behavior and properties of each state of matter.
Molecular energy determines how much the molecules move and interact with each other, which in turn affects the physical properties we observe.
For instance, the low energy in solids provides them with a defined shape, while the high energy in gases allows them to expand and fill any container they are placed in.

Density of Matter

Density refers to how closely packed the molecules in a substance are.
Among the three states of matter, solids have the highest density.
This is because their molecules are tightly packed together, resulting in a high mass per unit volume.
Liquids have a lower density compared to solids, though still higher than gases.
In liquids, the molecules have some freedom to move but are still relatively close to each other.
Gases have the lowest density due to the large amount of space between molecules.
The molecules in a gas are spread out and move freely, creating a low mass per unit volume.
The density of a substance affects its buoyancy and its behavior in different environments.
For instance, the high density of solids makes them less likely to float around in air, while the low density of gases allows them to disperse quickly.
Understanding density helps in comprehending why materials have certain weights and why some objects float while others sink.

Volume of Gases

One of the distinctive properties of gases is that they do not have a definite volume.
This means they will expand to fill any container they are in, regardless of the container's size.
In contrast, both solids and liquids possess a definite volume.
Solids maintain their shape and volume unless they are physically altered.
Liquids, while having a definite volume, take the shape of their container.
This behavior of gases is due to the high energy and freedom of movement of their molecules.
Because their molecules are so far apart and move so freely, gases can easily spread out and fill any space that is available.
The property of having no definite volume is fundamental to the use of gases in various applications, from inflating balloons to fuel combustion engines.
It also has practical implications, such as the need for pressurized containers to store gases efficiently.

Vibratory Motion of Solids

Even though solids have tightly packed molecules, those molecules are not completely motionless.
Instead, they possess what is known as vibratory motion.
This means that the molecules vibrate around their fixed positions within the solid structure.
The vibratory motion is a result of the thermal energy in the material.
The higher the temperature, the more vigorous the vibrations.
This motion is limited compared to the movement of molecules in liquids and gases.
The vibratory motion in solids is essential for understanding phenomena such as thermal expansion, where materials expand when heated.
It also plays a role in the transfer of thermal energy through conduction.
In essence, even though solids appear rigid and unchanging, their internal molecular vibratory motion is quite dynamic and important in many physical processes.