Elements, Compounds, Mixtures

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

Front

What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together. An example is carbon dioxide (CO2), which consists of carbon 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 saltwater.

Front

How many elements are in the compound H2O?

Back

There are 2 elements in H2O: hydrogen (H) and oxygen (O).

Front

What is the chemical formula for table salt?

Back

The chemical formula for table salt is NaCl, which consists of sodium (Na) and chlorine (Cl).

Front

What is the difference between a compound and a mixture?

Back

A compound is made of two or more elements chemically bonded together, while a mixture is a combination of substances that retain their individual properties.

Front

Give an example of a homogeneous mixture.

Back

An example of a homogeneous mixture is saltwater, where the salt is evenly distributed throughout the water.

Front

Give an example of a heterogeneous mixture.

Back

An example of a heterogeneous mixture is a salad, where the different ingredients can be seen and separated.

Front

What is the smallest unit of an element?

Back

The smallest unit of an element is an atom.

Front

What is a molecule?

Back

A molecule is a group of two or more atoms bonded together. For example, a water molecule (H2O) consists of two hydrogen atoms and one oxygen atom.