The Curse of Phlogiston

The video explores the historical development of the Flogiston theory, proposed by Johann Becker in 1667, which misled chemists for over a century. It highlights Henry Cavendish's experiments with zinc and acid, leading to the isolation of hydrogen, though he misidentified it as Flogiston. Joseph Priestley's work with mercury oxide led to the isolation of oxygen, but due to the prevailing Flogiston theory, its significance was not recognized. The video underscores how the Flogiston theory hindered the understanding of chemical elements.

What was the main idea behind Johann Becker's Flogiston theory?

• All gases are inflammable.

• All metals are made of mercury.

• All flammable substances contain flogiston.

• All substances contain oxygen.

What did Henry Cavendish mistakenly believe he had isolated during his experiments?

• Flogiston

• Carbon dioxide

• Nitrogen

• Oxygen

Which element did Henry Cavendish actually isolate?

• Oxygen

• Carbon

• Hydrogen

• Helium

What was Joseph Priestley's significant discovery during his experiments?

• He isolated oxygen.

• He discovered nitrogen.

• He found a new metal.

• He created a new compound.

Why did Joseph Priestley misinterpret his discovery of oxygen?

• He believed it was a form of flogiston.

• He considered it to be a liquid.

• He thought it was a new type of metal.

• He assumed it was a rare gas.