The modern term for "dephlogisticated air" is oxygen. This term originated from the phlogiston theory, which was an early scientific explanation of combustion and oxidation. In the late 18th century, Antoine Lavoisier identified oxygen as a key element in combustion processes, leading to the decline of the phlogiston theory.
Oxygen.
The gas is carbon dioxide.
The term "dephlogisticated air" historically refers to what is now known as oxygen. The concept originated from the phlogiston theory of combustion, which proposed that a substance called phlogiston was released during burning. When experiments showed that certain gases supported combustion and respiration, they were described as being "dephlogisticated," indicating the removal of phlogiston. Today, we understand these gases to be primarily oxygen.
Joseph Priestley, through experiments with gases, demonstrated that "dephlogisticated air" (what we now know as oxygen) was distinct from "fixed air" (carbon dioxide) by observing their different properties. He showed that dephlogisticated air supported combustion and respiration, while fixed air did not. Additionally, he found that dephlogisticated air produced a brighter flame and was absorbed by substances like rusting iron, which further distinguished it from fixed air. This helped lay the groundwork for understanding the composition of air and the nature of gases.
Joseph Priestley discovered that what he called "dephlogisticated air" was in fact oxygen. This discovery challenged the prevailing theory of phlogiston, and laid the foundation for understanding the role of oxygen in combustion and respiration. Priestley's work on oxygen was crucial in the development of modern chemistry.
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dephlogisticated air is oxygen gas; - so called by Dr. Priestly and others of his time.
Fixed air, known as carbon dioxide, is a gas that does not support combustion and can be absorbed by water, forming carbonic acid. In contrast, dephlogisticated air, which is oxygen, supports combustion and is necessary for fire to burn. To differentiate between them, you can perform a simple test: bubbling fixed air through lime water will turn it milky due to calcium carbonate formation, while dephlogisticated air will reignite a glowing splint. These reactions clearly demonstrate their distinct chemical properties.
Jan Ingenhousz collected samples of dephlogisticated air by conducting experiments on plants, particularly focusing on their ability to produce gas during photosynthesis. He used a setup that involved placing aquatic plants in sunlight and capturing the gases released in water. This allowed him to isolate and study the oxygen produced, which he referred to as "dephlogisticated air," distinguishing it from the carbon dioxide present in the atmosphere. His work laid foundational concepts for our understanding of photosynthesis and gas exchange in plants.
Jan Ingenhousz likely collected a sample of dephlogisticated air, which we now understand as oxygen, by using a method involving the photosynthesis of aquatic plants. He placed water plants in sunlight and observed that they released bubbles, which were primarily composed of oxygen. By capturing these bubbles in an inverted container filled with water, he could collect and analyze the gas, thus isolating what he termed dephlogisticated air. This experimentation contributed significantly to the understanding of gases involved in respiration and photosynthesis.
Ingenhousz demonstrated that oxygen (dephlogisticated air) was produced during photosynthesis by showing that plants release this gas in the presence of light. This was different from fixed air (carbon dioxide) because plants were observed to only release oxygen in the light, suggesting a direct relationship between the presence of light and the production of oxygen.