Oxygen vs. Phlogiston

Attribute	Oxygen	Phlogiston
Chemical symbol	O	N/A
Discovery	Discovered in 1774 by Joseph Priestley	Concept proposed in the 17th century
State at room temperature	Gas	N/A
Role in combustion	Supports combustion	Believed to be released during combustion
Role in respiration	Essential for respiration	Not involved in respiration

Introduction

Oxygen and phlogiston are two substances that were once believed to be fundamental to the understanding of combustion and respiration. While oxygen is a well-known element in the periodic table, phlogiston was a theoretical substance that was eventually disproven. In this article, we will compare the attributes of oxygen and phlogiston to understand the differences between these two concepts.

Physical Properties

Oxygen is a colorless, odorless gas that is essential for life on Earth. It is the most abundant element in the Earth's crust and plays a crucial role in respiration and combustion processes. Oxygen has a boiling point of -183 degrees Celsius and a melting point of -218 degrees Celsius. In contrast, phlogiston was believed to be a substance that was released during combustion. It was thought to have negative weight and was responsible for the process of burning.

Chemical Properties

Oxygen is a highly reactive element that readily forms compounds with other elements. It is essential for the process of oxidation, where substances combine with oxygen to produce heat and light. Oxygen is a key component of water (H2O) and many organic compounds. Phlogiston, on the other hand, was believed to be released during combustion and was thought to be responsible for the process of burning. However, phlogiston theory was eventually disproven with the discovery of oxygen.

Role in Combustion

Oxygen plays a crucial role in the process of combustion. When a substance burns, it combines with oxygen to produce heat and light. This process is known as oxidation and is essential for the release of energy from fuels. Without oxygen, combustion cannot occur, and fires would not be able to burn. Phlogiston theory, on the other hand, suggested that substances released phlogiston during combustion, which was later proven to be incorrect.

Discovery and Disproval

Oxygen was discovered by the Swedish chemist Carl Wilhelm Scheele in 1772 and independently by Joseph Priestley in 1774. They both observed that a substance was released during the process of combustion, which they named "dephlogisticated air." This substance was later identified as oxygen by Antoine Lavoisier. Phlogiston theory, on the other hand, was proposed by Johann Joachim Becher in the 17th century. The theory was eventually disproven by Antoine Lavoisier, who demonstrated that combustion involved the combination of substances with oxygen.

Modern Understanding

Today, oxygen is recognized as a fundamental element in chemistry and biology. It is essential for respiration in living organisms and plays a crucial role in many chemical reactions. Oxygen is used in various industries, including steel production, medicine, and aerospace. Phlogiston theory, on the other hand, has been completely discredited and is no longer considered a valid scientific concept. The discovery of oxygen and the development of modern chemistry have provided a more accurate understanding of combustion and oxidation processes.