Alchemy Final

Cavendish

gentleman’s scholar, discovers hydrogen

Black

discovers carbon dioxide, showed it would kill a sparrow

Priestly

religious dissenter, discovered oxygen with the pneumatic trough, advocate of the phlogiston theory

Academie des Sciences

Founded in 1666 by Louis XIV, limited paid positions

Lavoisier

father of chemistry, rejects alchemy publicly, rejects phlogiston theory, standardizes chemical language

Dalton

father of the atom, established law of partial pressures, considers chemical synthesis

Dalton’s theory of atoms (1807)

all matter is composed of solid, indivisible atoms surrounded by heat; a reaction is a reshuffling of atoms

chemical synthesis

chemical identities coming from the reshuffling of atoms, atoms combine in whole numbers

Temperature

the degree of hotness/coldness transferred between bodies

Specific heat

the amount of heat needed to raise the temperature of 1g of a substance by 1 degree

Lavoisier’s caloric heat

physical, the ‘heat fluid’ that flows from heated substances, connected with respiration

Ice calorimeter

the rate at how quickly ice melts is proportional to the heat generated

Count Rumford

American, rejects the idea of a physical caloric, connected heat with movement

thermodynamics

the study of heat and energy as they relate to work

Energy

the ability to do work, appears in many forms

Reactive

high potential energy

Stable

low potential energy

energy equation

e=q+w

1st law of thermodynamics

the total energy of the universe is constant

conservation of energy equation

E(universe)=E(system)+E(surroundings = 0

Enthalpy

the potential energy stored in the chemical bonds of a substance

Exothermic

a process that liberates heat from the system to the environment, H(rxn) is (-)

Endothermic

a process that requires heat from the environment to the system, H(rxn) is (+)

Hess’s law

the enthalpy charge of an overall process is the sum of all enthalpy changes of its individual steps

Favored reaction

H is negative

disfavored reaction

H is positive

Entropy (s)

the measure of disorder in a system

2nd law of thermodynamics

in any spontaneous process, the entropy of the universe increases

stoichiometry

increase in the number of moles, positively affects entropy

Gibbs Free Energy Equation

ΔG = ΔH - TΔS

G is negative

exorgonic and spontaneous

G is positive

endorgonic and not spontaneous

Joule

SI unit of energy

specific heat equation

Q = c x m x ΔT

Leyden jar

capacitator, produces a zap when both poles are touched

Volta

Italian, made voltaic piles

Voltaic pile

battery, alternating disks of metal (zinc, silver, etc.) separated by brine-soaked cloths

contact theory

electricity was generated by two metals touching each other

chemical theory

electricity is generated by chemical reactions

Humphry Davy

invented electrolysis, promoted both chemical and contact theory, proposed chemical affinity was related to electrical phenomenon

Berzelius

discovered silicon, thorium, selenium, thought all reactivity was based on electrical phenomena, used oxygen as a standard

Berzelius’s classification system

ponderables/imponderables, mineral/vegetable/animal

Prout

hypothesized atomic weights were whole numbers, sets hydrogen to 1

Diatomic

not understood until the Kalsruhe conference

Avogadro’s law (1811)

equal volumes of gases at the same temperature and pressure contain the same number of molecules, quantifies volumes of gases

Dobereiner

identified triads of elements similar in behavior/weight: halogens, alkaline earth metals

Chancourtis

wraps elements around a cylinder

Newlands

proposes law of octaves

Law of Octaves

when arranged by atomic weight, every eighth element is similar

Mendeleev

discoverer of the periodic table, left gaps to be filled in later, made both accurate and inaccurate predictions

Meyer

German, came to similar conclusions as Mendeleev but did not publish them

Ramsay and Rayleigh

discover argon in 1894

Ramsay

discovers noble gases: helium, neon, krypton, and xenon

Rutherford

discovers nitrogen

Atom

the smallest entity that possesses unique physical properties, electrically neutral

Nucleus

highly dense center of atom, composed of protons and neutrons, held together by strong force

proton

charge of +1

neutron

slightly larger than protons, assigned relative charge of 0

Electron cloud

makes up the volume of the atom, electrons are constantly moving

electron

relative charge of -1

atomic number

number of protons in an atom

atomic mass

weighted average of an element’s isotopes

radioactivity

the spontaneous disintegration of an unstable nucleus

alpha decay

emission of a helium nucleus (4, 2)

beta decay

nuclear transformations involving an electron or neutron, includes positron emission and electron capture

gamma decay

high-energy photon emission, occurs during most nuclear processes

Becquerel

discovers radioactivity, observes uranium

Marie Curie

searched for materials with radioactive properties, electrolyzed thorium salts to discover polonium and radium

Geissler

develops cathode tubes, discovers electrons

JJ Thomson

proposes the plum pudding model

Rutheford

discovers nucleus with the gold foil experiment

chadwick

detects the neutron by bombarding a lithium sample with alpha particles, develops artificial transmutation using an alpha emitter

q

heat (J)

m

mass (g)

c

specific heat capacity