Chemical Composition

Chemical composition refers to the identity and amount of the different substances that make up a sample of matter. Understanding the chemical composition of a substance is important in many fields, including chemistry, biology, and materials science.

Elements and Compounds

All matter is made up of elements, which are substances that cannot be broken down into simpler substances by chemical means. Elements are represented by chemical symbols, such as "H" for hydrogen and "O" for oxygen. When elements combine in fixed proportions, they form compounds. Compounds have unique properties that are different from the elements that make them up.

Chemical Formulas

Chemical formulas are used to represent the chemical composition of substances. For example, the chemical formula for water is H₂O, indicating that a water molecule is composed of two hydrogen atoms and one oxygen atom.

Studying Chemical Composition

To determine the chemical composition of a substance, scientists use a variety of techniques, including spectroscopy, chromatography, and mass spectrometry. These methods allow scientists to identify the elements and compounds present in a sample, as well as their relative amounts.

Study Guide

1. What is the difference between an element and a compound?
2. How are chemical formulas used to represent the composition of substances?
3. Explain the importance of studying chemical composition in scientific research.
4. Describe one method that scientists use to determine the chemical composition of a substance.