Test: Matter - Class 8 MCQ

Adhesion refers to the attraction between different types of particles. This property is important in various phenomena, such as water spreading on a surface, highlighting the interactions between different materials.

When a solid is heated, the energy of its particles increases, causing them to move more vigorously. This added energy can eventually lead to a change in state from solid to liquid, demonstrating the relationship between temperature and particle motion.

The kinetic molecular theory states that matter is composed of tiny particles that are constantly in motion. This movement and the energy associated with it determine the state of matter and its properties, forming a foundational concept in physical science.

During melting, the kinetic energy of particles increases as they absorb heat. This added energy allows solid particles to overcome the strong intermolecular forces that hold them in a fixed position, enabling them to move more freely as a liquid.

Intermolecular space refers to the empty space between particles in matter. This space varies depending on the state of matter—solid, liquid, or gas—affecting how particles interact and their overall properties.

Condensation is the process where water vapor (a gas) cools and turns back into liquid water. This is commonly observed when dew forms on grass in the morning, showcasing the transition from gas to liquid.

The law of conservation of mass concludes that mass remains constant before and after chemical reactions. This principle is fundamental to chemistry, ensuring that the total mass of reactants equals the total mass of products, regardless of the changes that occur during the reaction.

Liquids take the shape of their container because their particles are loosely packed, allowing them to flow and move around each other. This characteristic differentiates liquids from solids, which maintain a fixed shape.

In liquids, particles are loosely packed, allowing them to move around each other. This property enables liquids to take the shape of their container while maintaining a fixed volume, which distinguishes them from solids.

Melting refers to the process where a solid turns into a liquid when heated. During this change, the energy of the particles increases, allowing them to overcome their rigid structure and move more freely.

When gas particles cool down, they lose energy and move slower. This decrease in kinetic energy can lead to condensation, where gas transforms into a liquid as the particles come closer together due to increased intermolecular attraction.

The law of conservation of mass states that the total mass of matter remains constant before and after a chemical reaction. This principle is crucial in chemistry as it ensures that atoms are neither created nor destroyed, only rearranged.

Gas particles move freely with significant energy and have very weak intermolecular forces. This allows them to spread out and fill any container they are in, demonstrating the distinct properties of gases compared to solids and liquids.

Solids are characterized by having a fixed shape and size because their particles are closely packed together and strongly bonded. This strong attraction prevents them from changing shape when moved, which is a fundamental property of solids.

Matter changes its state (solid, liquid, gas) primarily due to changes in temperature and pressure. When energy is added (like heating), particles move faster, potentially changing from solid to liquid or gas, while cooling can reverse these changes.