Matter- Physical Science 8th Grade

A change in state or size refers to a physical change, where the substance undergoes a transformation in its physical properties without altering its chemical composition or identity. This could include processes like melting, boiling, freezing, condensation, or evaporation. Therefore, the correct answer is physical.

The three main states of matter are solid, liquid, and gas. These states are determined by the arrangement and movement of particles. In a solid, particles are tightly packed and vibrate in place. In a liquid, particles are close together but can move past each other. In a gas, particles are far apart and move freely. Ice is actually a form of solid water, so it falls under the category of solid.

Atoms are the smallest particles of matter. They are the basic building blocks of all elements and molecules. Atoms are composed of a nucleus, which contains protons and neutrons, surrounded by electrons. They cannot be broken down into smaller particles without losing their chemical properties. Therefore, atoms are considered the fundamental units of matter.

A change in a substance when a new substance is formed is referred to as a chemical change. This type of change occurs when the chemical composition of a substance is altered, resulting in the formation of a new substance with different properties than the original. Examples of chemical changes include combustion, rusting, and digestion.

A physical property of matter refers to a characteristic or quality that can be observed or measured without changing the substance's composition. Shape is a physical property as it describes the form or structure of an object. It can be determined by visually examining the object or measuring its dimensions. Reactivity, flammability, acidity, and basicity are not physical properties, but rather chemical properties, as they involve the substance's behavior in relation to other substances or its ability to undergo chemical reactions.

The formula for density is D = m/v, where D represents density, m represents mass, and v represents volume. This formula calculates the amount of mass per unit volume of a substance. By dividing the mass of an object by its volume, we can determine how tightly packed the particles are within the object, giving us the measure of density.

The mass of an object refers to the amount of matter it contains. It is a measure of the total quantity of material present in the object, regardless of its volume or composition. Mass is an intrinsic property of an object and is independent of external factors such as gravity. Therefore, the correct answer is "amount of matter."

The amount of space matter occupies is referred to as its volume. Volume is a measurement of the three-dimensional space that an object occupies. It is different from mass, weight, height, and width, as these terms do not specifically describe the space an object occupies.

A chemical property of matter refers to its ability to undergo a chemical reaction or change in composition when it interacts with other substances. Reactivity specifically relates to the tendency of a substance to react with other substances, either by combining with them or breaking apart. It indicates how easily a substance can undergo a chemical change and is an important characteristic when studying the behavior of matter in various chemical reactions.

In sublimation, a substance transitions directly from a solid state to a gaseous state without passing through the liquid state. This process occurs when particles gain enough energy to overcome the forces holding them in the solid phase and enter the gas phase. Common examples include dry ice (solid carbon dioxide) sublimating into carbon dioxide gas and iodine crystals turning directly into iodine vapor.