Test: Particulate Nature of Matter - Class 8 MCQ

The term for the distance between particles is called interparticle spacing. In solids, this spacing is minimal due to strong interparticle attractions, while in gases, the spacing is much larger, allowing for free movement. This concept is essential for understanding the properties of different states of matter.

When sugar is dissolved in water and stirred, the sugar particles break down into their constituent particles and occupy the interparticle spaces between water molecules. This results in a homogeneous solution where the sugar is not visible, demonstrating the concept of solubility and the behavior of particles in liquids.

Gas particles have the highest thermal energy compared to solids and liquids. This high energy allows gas particles to move freely and rapidly in all directions, which is why gases can fill a container entirely. Understanding this concept is key in thermodynamics and gas behavior.

When a solid is heated to its melting point, the increased energy causes its particles to vibrate more vigorously, leading to a weakening of the interparticle forces. Eventually, the particles start to move apart, transitioning the solid into a liquid state. This phase change is a fundamental concept in understanding the behavior of matter.

Some solids, like sand, do not dissolve in water because their particles are held together too tightly. The strong interparticle attractions in sand prevent the water particles from pulling them apart. This concept is critical in understanding solubility and the behavior of different materials in liquids.

Liquids have a definite volume because their particles are close together and cannot be easily compressed. However, they do not have a fixed shape because the particles can move past each other, allowing liquids to take the shape of their containers. This unique property is essential for many everyday applications, such as pouring drinks.

Solids retain their shape because the particles are held in fixed positions by strong interparticle attractions. These forces ensure that the particles cannot easily move apart, allowing solids to maintain a definite shape and volume. This characteristic is vital in structural applications, where rigidity is required.

In gases, the interparticle attractions are almost negligible, which allows the particles to move freely in all directions. This lack of attraction results in gases having no fixed shape or volume, enabling them to fill any container they occupy. This principle is crucial in understanding gas behavior in various applications.

Gas particles are compressible and can expand to fill any available space. This is due to the large gaps between particles and negligible interparticle attractions, which allows gases to adapt to the shape and volume of their container. This property is significant in various applications, including gas storage and transport.

Heating a liquid increases the energy of its particles, leading to more vigorous movement. As the temperature rises, the particles move faster and can eventually reach the boiling point, where they will transition into the gaseous state. This relationship between temperature and particle movement is fundamental in thermodynamics.

The state of matter is primarily determined by the strength of interparticle attractions and the spacing between particles. Strong attractions and minimal spacing result in solids, while weaker attractions and greater spacing lead to liquids and gases. Understanding these factors is essential in the study of physical chemistry and material science.

As matter transitions from solid to liquid, the interparticle spacing increases. This occurs because the heat energy causes the particles to vibrate more vigorously, breaking some attractions and allowing them to move further apart. This change is crucial in understanding the melting process and the properties of liquids.

Gas particles in a closed container spread out to fill the entire space available to them. This behavior is due to their high energy and negligible interparticle attractions, allowing them to move freely and occupy any volume. This property is essential in understanding gas laws and the behavior of gases under different conditions.

Thermal energy determines how far apart particles are and how they move in different states of matter. In solids, low thermal energy results in minimal movement, while in gases, high thermal energy allows for rapid particle movement and large spacing. This relationship is fundamental in understanding the behavior of matter under varying temperatures.

When the plunger of a syringe filled with gas is pulled, the gas expands and fills the entire syringe. This is due to the large gaps between gas particles, which allows them to move freely and fill any available space. This principle is a practical demonstration of gas behavior and compressibility.

The process by which a liquid turns into vapor at its boiling point is called boiling. This transition occurs when the particles gain enough thermal energy to break free from the liquid state and move into the gaseous state. Boiling can be observed in cooking, such as when water reaches 100°C.

The smallest unit that makes up all matter is called a constituent particle. These particles are the fundamental building blocks of substances and cannot be divided further by normal means. Understanding this concept helps in grasping how different materials are formed at a microscopic level.

When chalk is ground into a fine powder, the size of the particles changes, but it remains chalk, illustrating a physical change. The chemical composition does not change, as the substance still consists of the same constituent particles. This principle highlights the distinction between physical and chemical changes in matter.

Evaporation is the process where liquid turns into vapor only at the surface, occurring at all temperatures, while boiling happens throughout the liquid at a specific temperature (the boiling point). Understanding this distinction helps clarify how different phase changes occur under varying conditions.

Solids have particles that are tightly packed together with strong interparticle attractions. This arrangement allows them to maintain a definite shape and volume, resulting in minimal movement aside from vibrations. This is why solids feel rigid and maintain their form.