Unit 1 and 2 Review

Front

What is a pure substance?

Back

A pure substance is a material that has a constant composition and consistent properties throughout. Examples include elements and compounds.

Front

What is a heterogeneous mixture?

Back

A heterogeneous mixture is a combination of two or more substances that are not uniformly distributed, meaning the different components can be seen and separated. Example: salad.

Front

What is a homogeneous mixture?

Back

A homogeneous mixture is a mixture in which the composition is uniform throughout. Example: saltwater.

Front

What is a chemical change?

Back

A chemical change is a process that involves the transformation of one or more substances into different substances, often with energy changes. Example: burning wood.

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. Example: crushing ice.

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include gold, oxygen, and hydrogen.

Front

What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together. Example: water (H2O).

Front

How can you identify a chemical change?

Back

Indicators of a chemical change include color change, gas production, temperature change, and the formation of a precipitate.

Front

What is the difference between a physical and chemical change?

Back

A physical change affects the form of a substance but not its chemical composition, while a chemical change results in the formation of new substances.

Front

What is the significance of the law of conservation of mass in chemical reactions?

Back

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