A description of the sequence of steps by which a chemical reaction takes place is called a reaction mechanism. Many studies go into trying to determine possible
It is often seen as linked to the quest to turn lead or another common starting material into gold,  though in ancient times the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, movement, growth, embodying, disembodying, drawing the spirits from bodies and bonding the spirits within bodies by the early 4th century Greek-Egyptian alchemist Zosimos.
The current model of atomic structure is the quantum mechanical model. This matter can be studied in solid, liquid, or gas statesin isolation or in combination. The interactionsreactions and transformations that are studied in chemistry are usually the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together.
Such behaviors are studied in a chemistry laboratory.
The chemistry laboratory stereotypically uses various forms of laboratory glassware. Solutions of substances in reagent bottles, including ammonium hydroxide and nitric acidilluminated in different colors A chemical reaction is a transformation of some substances into one or more different substances.
It can be symbolically depicted through a chemical equationwhich usually involves atoms as subjects.
The number of atoms on the left and the right in the equation for a chemical transformation is equal. When the number of atoms on either side is unequal, the transformation is referred to as a nuclear reaction or radioactive decay.
The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws. Energy and entropy considerations are invariably important in almost all chemical studies.
Chemical substances are classified in terms of their structurephase, as well as their chemical compositions. They can be analyzed using the tools of chemical analysise. Scientists engaged in chemical research are known as chemists. Several concepts are essential for the study of chemistry; some of them are: Matter In chemistry, matter is defined as anything that has rest mass and volume it takes up space and is made up of particles.
The particles that make up matter have rest mass as well — not all particles have rest mass, such as the photon. Matter can be a pure chemical substance or a mixture of substances. Atom A diagram of an atom based on the Bohr model The atom is the basic unit of chemistry.
It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons together called nucleonswhile the electron cloud consists of negatively charged electrons which orbit the nucleus.
In a neutral atom, the negatively charged electrons balance out the positive charge of the protons. The nucleus is dense; the mass of a nucleon is appromixately 1, times that of an electron, yet the radius of an atom is about 10, times that of its nucleus.
Chemical element A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z.
The mass number is the sum of the number of protons and neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same atomic number, they may not necessarily have the same mass number; atoms of an element which have different mass numbers are known as isotopes.
For example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbonbut atoms of carbon may have mass numbers of 12 or The periodic table is arranged in groupsor columns, and periodsor rows.
The periodic table is useful in identifying periodic trends. Chemical compound A compound is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements.
Organic compounds are named according to the organic nomenclature system. When a compound has more than one component, then they are divided into two classes, the electropositive and the electronegative components. In this scheme each chemical substance is identifiable by a number known as its CAS registry number.
A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well for substances that are composed of molecules, which is not true of many substances see below.
Molecules are typically a set of atoms bound together by covalent bondssuch that the structure is electrically neutral and all valence electrons are paired with other electrons either in bonds or in lone pairs.
Thus, molecules exist as electrically neutral units, unlike ions. When this rule is broken, giving the "molecule" a charge, the result is sometimes named a molecular ion or a polyatomic ion. However, the discrete and separate nature of the molecular concept usually requires that molecular ions be present only in well-separated form, such as a directed beam in a vacuum in a mass spectrometer.
Charged polyatomic collections residing in solids for example, common sulfate or nitrate ions are generally not considered "molecules" in chemistry. Some molecules contain one or more unpaired electrons, creating radicals. Most radicals are comparatively reactive, but some, such as nitric oxide NO can be stable.May 29, · This video is part of a lecture undergraduate-level course titled "General Chemistry" taught at UC Irvine by Ramesh D.
Arasasingham, Ph.D. Recorded May 29, Index of Topics. AP Chemistry is an in-depth, fast-paced second-year chemistry course for advanced, science-oriented students.
The course will provide students with a thorough grounding in chemical principles and quantitative reasoning, with an emphasis on inorganic chemistry. This site has been developed primarily as a resource for UO chemistry instructors, but high school and college chemistry and physical science instructors can find a lot of useful information here too.
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