SciRev. X102 Exam 3 wk. 10 Chemistry exam ( 41 questions and answers )

alchemy

-the practice and theory dating from medieval times involving matter and its transformations (finding out what is stuff by changing it)

-one of its main goals, though not the only one, was to make gold from other metals and substances (transmutation)

-didn't make gold, just observed it to understand its matter and its properties

-employed an obscure, often sexualized language

~ex. "Our crude sperm flows from a trinity of immature substances.... of which two... become a pure milky vir-gin-like Nature drawn from the menstruum of the sordid wh-ore"

-contributed to understanding matter and its properties

some alchemists developed advanced laboratory practices and used a form of......

weight balance in chymical reactions

chymestry

-a discipline including both chemical and alchemical practices

Georg Ernest Stahl

-was an influential physician in Halle

-defended the role of an immaterial soul in physiology

-thought okay, there may be mechanisms that occur in the body but all the mechanisms are controlled by a soul

-leading chemist who relied on the notion of phlogiston

phlogiston

-a substance supposed by 18th-century chemists to exist in all combustible bodies, and to be released in combustion; burnt up/inflammable

-combustible bodies contained an oily earth (phlogiston) that was released during combustion (is the opposite of what we know today)

-is a fiery substance fixed in combustible bodies, which is released when those bodies burn

-ex. coal

coal (phlogiston)

-according to phlogiston theory, it is rich in phlogiston

-it's released when coal burns, leaving behind ashes

calcination

-would release phlogiston

-was the burning or roasting process to produce a calx (=oxide), once phlogiston has been released

calx

-an elemental substance that had lost its phlogiston

-calx revealed a problem in the phlogiston theory: calx of a metal weighed more than the metal (weight anomaly)

phlogiston was helpful in explaining...

-combustion

-respiration

-calcination

weight anomaly

-w/ calx

-explained by arguing that phlogiston may have lightness or negative weight (as in the ancient aristotelian system, when fire had "levity"

Was phlogiston proven real or fake??

-turned out not to exist: combustion often involved combination w/ oxygen rather than release of phlogiston

calx of lead

known as litharge

remember: 4 aristotelian primary elements were...

-earth, water, air, and fire

-were naturally hot or cold, wet or dry, solid or fluid

Was air found to be homogeneous (as in w/ aristotelian philosophy?) in the 17th century?

-no, it's not a homogenous element

-consisted of many different components, one of which was active in respiration

-collecting and identifying those components proved difficult

inflammable air

-was collected by dissolving metals in acids

-was 11x lighter than common air and exploded w/ a bang

-a balloon filled w/ inflammable air raised in atmospheric air

what was 'fixed air' originally thought of?

was taken to be normal air fixed in a solid substance

how is fixed air produced?

by burning the calx of a metal in the presence of coal

Joseph Black

-fixed air became a type of air w/ specific properties

-was found to extinguish a flame as if 'the burning material had been dipped in water' and to hinder respiration

what was reduction?

process of restoring the metal

air produced by the reduction of the calx of mercury was initially assumed to be...

fixed air, but it proved to have very different properties

Joseph Priestley

-religious views were so radical for the time that a mob burnt down his house; he fled to pennsylvania

-performed many experiments

-one included heating the calx of mercury to obtain a gas he called dephlogisticated air, differing from fixed air

dephlogisticated air

oxygen

Priestley's Experiment

-apparatas was used to collect a gas by heating the calx of mercury on a furnace (used a burning lens)

-performed several tests showing that it allowed respiration and combustion

-therefore it wasn't fixed air

who coined the terms oxygen and hydrogen?

-Lavoisier, who worked w/ his wife Paulze

-oxygen = acid-former

-hydrogen = water-former

calcination and reduction of lead: Phlogiston theory

-calcination:

lead -> calx of lead + phlogiston

-reduction:

calx of lead + coal (rich in phlogiston) -> lead

calcination and reduction of lead: Lavoisier

-calcination:

lead + common air -> calx of lead (lead oxide)

-reduction:

calx of lead + coal -> lead + fixed air

types of air

-fixed air

-nitrous air

-inflammable air

-dephlogisticated air

fixed air

carbon dioxide

nitrous air

nitrogen oxide

inflammable air (type of air)

hydrogen

dephlogisticated air

oxygen

In the 18th century, investigators realized that chemical elements....

-were not associated w/ a physical state (solid, fluid, or gas)

-states depended on temperature and pressure

chemical revolution

-lavosier established chemistry on a new basis and talked of a 'chemical revolution'

-Cavendish and Laboisier found the dew thus forming to be water (finding that water isn't an element but a compound)

how did Cavendish and Lavosier find the dew that formed water?

saw that inflammable air (hydrogen) in common air, where it combines w/ oxygen, it exploded w/ an electric spark

lavosier established what....

-a new rigorous and systematic language for chemistry

-including names that characterized unambiguously the compounds involved

-similar to how what Linnaeus had done for botany

heat

-considered to be a substance in the 18th century, much like air (some thought the same about cold)

-much like air, heat could be fixed in matter

-this is what some thought latent heat was, heat combined w/ matter

latent heat

heat combined w/ matter

caloric

-introduced by lavoisier (who denied phlogiston's existence)

-a fluid that was the substance of heat

-was constant in the universe and which was flowing from hot to cold bodies

what did lavoisier think was a substance?

-caloric (substance of heat)

-light

was heat a substance?

finding that heat wasn't a major substance was a major finding established in the 19th century

enlightenment*

-shift in ideas about knowledge away from traditional sources of authority

-age of reason

-included individual liberty, progress of civilication, religious tolerance, etc