Manhattan Project - Chemistry Encyclopedia
Nuclear scientists knew in the 1930s that there was a tremendous amount of energy locked in the atomic nucleus. The problem was how to access this energy.
Materials Science - Chemistry Encyclopedia
After World War II, the application of materials became less empirical and more founded in scientific principles. The term "materials science" emerged in the 1960s to reflect this trend and the realization that solutions to many of the world's most challenging technological problems were increasingly materials-limited.
Measurement - Chemistry Encyclopedia
Membrane - Chemistry Encyclopedia
All living creatures are made of cells. One cellular component, the membrane, plays a crucial role in almost all cellular activities.
Mendelevium - Chemistry Encyclopedia
Mercury - Chemistry Encyclopedia
Methylphenidate - Chemistry Encyclopedia
Ritalin, the trademarked name of methylphenidate, is commonly prescribed to children ages 7–18 with attention-deficit hyperactivity disorder.
Minerals - Chemistry Encyclopedia
Minerals are the building blocks of rocks. A mineral may be defined as any naturally occurring inorganic solid that has a definite chemical composition (that can vary only within specified limits) and possesses a crystalline structure.
Mole Concept - Chemistry Encyclopedia
In chemistry the mole is a fundamental unit in the Système International d'Unités, the SI system, and it is used to measure the amount of substance. This quantity is sometimes referred to as the chemical amount.
Molecular Geometry - Chemistry Encyclopedia
Molecules, from simple diatomic ones to macromolecules consisting of hundreds of atoms or more, come in many shapes and sizes. The term "molecular geometry" is used to describe the shape of a molecule or polyatomic ion as it would appear to the eye (if we could actually see one).
Molecular Modeling - Chemistry Encyclopedia
A model is a semblance or a representation of reality. Early chemical models were often mechanical, allowing scientists to visualize structural features of molecules and to deduce the stereochemical outcomes of reactions.
Molecular Orbital Theory - Chemistry Encyclopedia
Molecular Structure - Chemistry Encyclopedia
Throughout history, humans have created models to help them explain the observed character of substances and phenomena in the material world. The ancient philosophers Democritus and Lucretius were among the first to speculate that matter was discontinuous, and that small, indivisible particles not only made up substances but also gave them their observed properties.
Molecules - Chemistry Encyclopedia
A molecule is the smallest entity of a pure compound that retains its characteristic chemical properties, and consequently has constant mass and atomic composition. It is an assembly of nonmetallic atoms held together into specific shapes by covalent bonds.
Molybdenum - Chemistry Encyclopedia
Mutagen - Chemistry Encyclopedia
Mutagens are chemical agents that cause changes in the genetic code which are then passed on to future generations of an organism. Mutations are usually chemical in nature and often carcinogenic, but may also be caused by physical damage produced by x rays or other causes.
Mutation - Chemistry Encyclopedia
Any heritable change in the genetic information or DNA is called a mutation. A change in the base sequence of DNA that is then replicated and transmitted to future generations of cells becomes a permanent change in the genome.
Nanochemistry - Chemistry Encyclopedia
In recent years nanoscale science and technology have grown rapidly. Nanochemistry, in particular, presents a unique approach to building devices with a molecular-scale precision.
Marsden, Ernest - Chemistry Encyclopedia
Ernest Marsden studied at the University of Manchester under Ernest Rutherford and Hans Geiger. Although a physicist, he would help elucidate something of value to all chemists: the internal structure of the atom.
Martin, Archer John Porter - Chemistry Encyclopedia
Very few chemical reactions produce clean, pure products with no trace of starting materials or impurities. Most generate a mixture whose individual components must be purified before the results can be identified.
Maxwell, James Clerk - Chemistry Encyclopedia
James Clerk Maxwell is generally regarded as one of the outstanding physicists of the nineteenth century. He made important advances in the theory of electricity and magnetism, as well as in thermodynamics and the kinetic theory of gases.
Meitner, Lise - Chemistry Encyclopedia
On any list of scientists who should have won a Nobel Prize but did not, Lise Meitner's name would be near the top. She was the physicist who first realized that the atomic nucleus could be split to form pairs of other atomic nuclei—the process of nuclear fission.
Mendeleev, Dimitri - Chemistry Encyclopedia
Russian chemist Dimitri Mendeleev, who devised the atomic mass-based Periodic Table.
Menten, Maud - Chemistry Encyclopedia
When biochemists are asked to name a mathematical relationship, it is almost certain that they will choose the Michaelis–Menten equation. This equation enables biochemists to study quantitatively the way in which an enzyme speeds up a biochemical reaction.
Meyer, Lothar - Chemistry Encyclopedia
Lothar Meyer was the son and grandson of physicians, so it was only natural that initially he decided on a career as a physician. At the age of twenty-one, he began his studies in medicine at the University of Zurich and received his M.D.
Millikan, Robert - Chemistry Encyclopedia
Morgan, Agnes Fay - Chemistry Encyclopedia
Born in Peoria, Illinois, on May 4, 1884, Agnes Fay Morgan excelled in high school and studied chemistry at the University of Chicago. After receiving a master of science in chemistry in 1905, she spent the next several years teaching at various colleges across the United States.
Moseley, Henry - Chemistry Encyclopedia
English physicist Henry Moseley, who arranged the Periodic Table in order of the atomic numbers of the elements.