8 NC Check-In Review Physical Science

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include boiling water, melting ice, and shredding paper.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. Examples include rusting iron, burning coal, and baking a cake.

Front

What happens to molecules in a substance when it is heated?

Back

When a substance is heated, its molecules gain energy and begin to move faster.

Front

What is the law of conservation of mass?

Back

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of the reactants equals the total mass of the products.

Front

What is photosynthesis?

Back

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll, converting carbon dioxide and water into glucose and oxygen.

Front

What is the difference between renewable and non-renewable energy sources?

Back

Renewable energy sources can be replenished naturally (e.g., solar, wind, hydroelectric), while non-renewable energy sources are finite and will eventually deplete (e.g., coal, oil, natural gas).

Front

What is density?

Back

Density is the mass of a substance divided by its volume, often expressed in grams per cubic centimeter (g/cm³). It determines whether an object will float or sink in a fluid.

Front

What is a precipitate?

Back

A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.

Front

What is the role of catalysts in chemical reactions?

Back

Catalysts are substances that speed up chemical reactions without being consumed in the process.

Front

What is an example of a physical change?

Back

An example of a physical change is freezing water to make ice.