atoms, elements, molecules and compounds

Front

Hydrogen is a pure substance represented by the chemical symbol H. Which of the following best describes hydrogen?

Back

Hydrogen is an element made of only one kind of atom.

Front

The element oxygen, represented by the symbol O, is classified as

Back

a pure substance

Front

What are carbon, hydrogen, and methane classified as?

Back

carbon and hydrogen are elements and methane is a compound.

Front

What is a compound?

Back

a substance in which the atoms of two or more elements are combined together

Front

The chemical combination of two or more different kinds of atoms in fixed amounts is called a(n)

Back

compound

Front

Atoms combine to form _______.

Back

molecules

Front

A compound is...

Back

a substance formed by the reaction of two or more elements.

Front

Carbon dioxide is formed when two oxygen atoms chemically combine with a carbon atom. Which term best describes carbon dioxide?

Back

compound

Front

What defines a mixture?

Back

can be broken down into its basic substances through physical means

Front

The air we breathe contains different individual gases (mostly nitrogen and oxygen). Which of the following correctly describes the air we breathe? Options: compound, liquid, element, mixture

Back

mixture