TeXes Science Practice Test

What is defined as a substance containing two or more chemical elements held together by chemical bonds?

1. A mixture

2. An element

3. A compound

4. An atom

The correct answer is: A compound

A substance containing two or more chemical elements held together by chemical bonds is known as a compound. Compounds can be formed through various types of chemical bonds, such as ionic or covalent bonds, which link the different elements together in a definite ratio. For example, water (H₂O) is a compound made of hydrogen and oxygen atoms chemically bonded together. In contrast, a mixture consists of two or more substances that are physically combined but not chemically bonded, meaning they can vary in composition and retain their individual properties. An element is a pure substance that cannot be broken down into simpler substances by chemical means and is made up of only one type of atom. An atom itself is the smallest unit of an element, retaining the properties of that element. Therefore, understanding these definitions clarifies why the concept of a compound specifically refers to the chemical bonding of two or more different elements.