History of Chemistry Flashcards

Flashcards covering key historical figures and discoveries in chemistry.

Latent Heat

Substances absorb or release heat during phase changes without a change in temperature.

Count Rumford's Theory of Heat

Heat can be generated indefinitely through mechanical motion, suggesting heat is a form of energy.

William Thomson (Lord Kelvin)

Introduced the absolute temperature scale and helped formulate the Second Law of Thermodynamics.

Josiah Willard Gibbs

Developed the concept of free energy and phase diagrams, introducing chemical thermodynamics.

Pasteur's Contribution to Stereochemistry

Discovered molecular chirality by separating enantiomers of tartaric acid.

Friedrich Wöhler

Synthesized urea from ammonium cyanate, proving organic compounds could be made from inorganic substances.

Kekulé's Contribution to Benzene

Proposed the ring structure of benzene with alternating single and double bonds.

Valency in Organic Chemistry

Explained how atoms form a specific number of bonds, helping predict molecular structures.

Mendeleev's Use of 'Eka'

Used 'eka' to name undiscovered elements (e.g., eka-silicon for germanium) based on predicted properties.

Helium

First observed in the sun's spectrum before being discovered on Earth.

Marie Curie's Discovery

Isolated two new radioactive elements (polonium and radium) based on their unique properties.

Discovery of Noble Gases

Required the addition of a new group (Group 18) to the periodic table.

Adolf von Baeyer

Synthesized indigo dye, contributing to the development of the synthetic dye industry.

Felix Hoffmann (Aspirin)

Modified salicylic acid to reduce its stomach-irritating effects, creating aspirin.

Alfred Nobel's Motivation

Sought to leave a legacy that honored human advancement and peace.

Ellen Swallow Richards

Pioneered water quality testing, established home economics, and worked on air and food safety.

G.N. Lewis' Octet Rule

Atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight electrons.

Wolfgang Pauli's Exclusion Principle

No two electrons in an atom can have the same set of quantum numbers.

Heisenberg Uncertainty Principle

You cannot simultaneously know both the exact position and momentum of a particle.

Molecular Bond Theories

Valence Bond Theory and Molecular Orbital Theory.

Rosalind Franklin's Contribution

X-ray diffraction images of DNA (especially Photo 51) provided critical evidence for the double helix model.

Wallace Hume Carothers

Developed nylon, the first synthetic fiber, as an alternative to silk.

Dorothy Hodgkin's Technique

X-ray crystallography.

Stanley Miller's Experiment

Simulated early Earth's atmosphere and produced amino acids from simple gases using electrical sparks.

Leopold Ruzicka

Challenged the assumption that large carbon rings couldn't exist and synthesized macrocyclic compounds.

Kathleen Lonsdale

Confirmed the flat, hexagonal structure of benzene using X-ray crystallography.

Frontier Orbital Theory

Explains chemical reactivity in terms of interactions between the highest occupied and lowest unoccupied molecular orbitals.

Geoffrey Wilkinson and Ernst Otto Fischer

Their work on organometallic sandwich compounds, especially ferrocene.

Harcourt and Esson

Developed differential rate laws to describe how reaction rates depend on concentrations.

Irving Langmuir

Proposed a model for adsorption of gases on surfaces and introduced the concept of the monolayer.

Oscillating Chemical Reactions

Showed that reactions could proceed non-linearly and in cycles.

Max Bodenstein

Studied reaction kinetics, especially chain reactions and the concept of steady-state approximation.

Primary Forms of Radiation

Alpha particles, beta particles, and gamma rays.

Joliot-Curies

Discovered artificial radioactivity by bombarding elements with alpha particles to create radioactive isotopes.

Uranium-235 Isolation

Separating the rare U-235 isotope from the more abundant U-238, which are chemically identical.

George von Hevésy

He dissolved the medals in aqua regia to hide them from the Nazis and later recovered the gold to recast them.