Exam 2 Question 2
1. Trace the development of chemistry as a modern science over the seventeenth and eighteenth centuries. Who was the phlogiston theory and why did I become such a barrier to progress of chemistry?
a. Phlogiston Theory developed in the early eighteenth century by Georg Ernst Stahl, all materials consists of two substances. One is phlogiston, which is given off when the materials burns; the other is what remains following combustion. Calx is the leftover "ash" after the substance has burned. The advanced of chemistry was stymied for nearly 100 years by fruitless attempts to isolate and identify phlogiston.
Discuss the contributions of (at least) Robert Boyle,
b. Robert Boyle too works with gasses further and made the first significant steps in reviving Democritus Atomic Theory. He constructed an air pump and conducted pioneering experiments in which he demonstrated the physical characteristics of gasses, the nature of a vacuum, and the necessary role of air in combustion, respiration, and transmission of sound. His statement, Boyle's Law, that the volume of a gas is inversely proportional to its temperature at constant pressure, may be regarded as the first law in chemistry. Boyle made the first significant attack on the Aristotelian "four components' theory, arguing that the four components could not be true elements because they could not combine to form other substances, nor could they be extracted from other substances.
Discuss the contributions of (at least) Joseph Prierstly
c. Joseph Priestly discovered "dephlogisticated air". This "air" was present in atmospheric air before burning but absent after burning, apparently replaced by the phlogiston released from burning, hence "air without phlogiston."
Discuss the contributions of (at least) John Dalton
d. John Dalton resurrected Democritus Atomic Theory and combined it with the empirical and theoretical advances of the preceding century regarding elements, compounds, and chemical reactions. In Daltons Atomic Theory elements are composed of small, indivisible, and indestructible atoms, which retain their elemental identify through all chemical reactions.
Discuss the contributions of (at least) John Dalton
e. Antoine Lavoisier made several critical discoveries that collectively broke the phlogiston impasse and transformed chemistry from alchemical meddling to a predictable quantitative science. Antoine is credited for the Oxygen Theory of Combustion, which is not a substance, but a chemical process. Priestly discovered "dephlogisticated air" but Lavoisier renamed it "oxygen" and correctly described its role in combustion. As well as the Law of Conservation of Mass which is in chemical reactions, matter may be recombined, but is neither created nor destroyed. Antoine developed much of the modern Mathematical, nomenclature, and classification systems in modern chemistry (chemical equations, naming chemical compounds, etc. Lavoisier made chemistry a true science - quantifiable, predictable, with fundamental set of descriptive and mechanistic theories and laws
