Unit 2: Element, Compound, Mixture

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 hydrogen (H), oxygen (O), and gold (Au).

Front

What is a compound?

Back

A compound is a substance formed when two or more elements chemically bond together. For example, water (H2O) is a compound made of hydrogen and oxygen.

Front

What is a mixture?

Back

A mixture is a combination of two or more substances that are not chemically bonded. Examples include air, salad, and sand and salt.

Front

What is the difference between a compound and a mixture?

Back

A compound has a fixed composition and properties, while a mixture can vary in composition and retains the properties of its individual components.

Front

What is a homogeneous mixture?

Back

A homogeneous mixture is a mixture that has a uniform composition throughout. An example is saltwater.

Front

What is a heterogeneous mixture?

Back

A heterogeneous mixture is a mixture that does not have a uniform composition. An example is a salad or a mixture of sand and pebbles.

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. Examples include rusting iron and 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. Examples include melting ice and dissolving sugar in water.

Front

What are the properties of metals?

Back

Metals are typically shiny, good conductors of heat and electricity, malleable, and ductile. Examples include iron, copper, and aluminum.

Front

What are the properties of nonmetals?

Back

Nonmetals are usually dull, poor conductors of heat and electricity, and brittle in solid form. Examples include sulfur, oxygen, and carbon.