Question

Passage

For over a century, the phlogiston theory dominated chemical philosophy. Proposed by Johann Joachim Becher and refined by Georg Ernst Stahl, the theory posited that all combustible materials contained a fire-like element called phlogiston, which was released into the air during burning. When a substance burned, it lost phlogiston, leaving behind a "calx" (residue). A key piece of evidence supporting this was that charcoal, which burned almost entirely away, was thought to be nearly pure phlogiston.

However, anomalies began to accumulate. When metals were burned, or "calcined," the resulting calx was heavier than the original metal. If phlogiston had been lost, the weight should have decreased. Supporters of the theory attempted to resolve this by claiming phlogiston had "negative weight" or was lighter than air, but these explanations grew increasingly strained.

The decisive shift came in the late eighteenth century through the work of Antoine Lavoisier. Recognizing that the negative weight hypothesis was physically untenable, Lavoisier conducted meticulous quantitative experiments sealing substances in closed vessels. He demonstrated that when metals calcined, they absorbed a specific component of the air, which he eventually named oxygen. Instead of losing an invisible substance, the metals gained weight because they combined with this gas. Lavoisier’s oxygen theory did not merely add to existing chemical knowledge; it fundamentally restructured the discipline by introducing the law of conservation of mass and establishing a new chemical nomenclature, rendering phlogiston obsolete.

Which of the following statements best summarizes the passage's central argument regarding the transition from the phlogiston theory to Lavoisier's oxygen theory?