Making Sense of Dalton’s PlayhousePriestley’s Experiment (Exp. #1)

Mercury calx

Priestly discovered that when mercury calx was heated, it did not just turn into only mercury• A strange new gas was also formed in addition

to mercury• “what surprised me more than I can well

express was that the candle burned in this gas with a remarkably vigorous flame”

Main Thing to Take Away: Priestley’s discovery revealed that substances could combine together or break apart to form new substances with different properties

Lavoisier’s Experiment• Lavoisier knew from other scientists before him that acids react with some metals to

release another strange and highly flammable gas called “phlogiston”• Lavoisier mixed the 2 gases, phlogiston and the newly renamed oxygen, in a closed glass

container and inserted a match

• Phlogiston immediately burned in the presence of oxygen and afterwards he observed droplets of water on the glass container

• Realized that the water was formed by the reaction between phlogiston and oxygen

• Renamed phlogiston—hydrogen! (greek word for “water maker”)

From such observations and calculations, Lavoisier established the Law of Conservation of Mass • Mass is not lost or gained during a chemical

reaction

Diamond ExperimentMid-1600s: Robert Boyle showed that when exposed to intense heat, diamonds appeared to “disappear”• Over 100 years later, experiment was conducted where diamonds were placed in

container, free of air, and exposed to intense heat. Diamonds were found to be red hot….but unaffected by the heat

• Soon after, our diamond experiment was performed….

.20 g of diamond produced same amount of product as .20 g of charcoal—suggesting charcoal and diamond are made from same material (carbon)

Because the mass of the product doubled when you doubled the amount of diamond/charcoal—it suggests that elements combine in specific, defined ratios in chemical reactions

Diamonds Aren't Forever