Search results
Results from the WOW.Com Content Network
Protactinium-231 is the longest-lived isotope of protactinium, with a half-life of 32,760 years. In nature, it is found in trace amounts as part of the actinium series , which starts with the primordial isotope uranium-235 ; the equilibrium concentration in uranium ore is 46.55 231 Pa per million 235 U.
However, the 231 Pa (with a half-life of 3.27 × 10 4 years) formed via (n,2n) reactions with 232 Th (yielding 231 Th that decays to 231 Pa), while not a transuranic waste, is a major contributor to the long-term radiotoxicity of spent nuclear fuel. While 231 Pa can in principle be converted back to 232
Theoretical chemistry requires quantities from core physics, such as time, volume, temperature, and pressure.But the highly quantitative nature of physical chemistry, in a more specialized way than core physics, uses molar amounts of substance rather than simply counting numbers; this leads to the specialized definitions in this article.
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
Physical organic chemistry is the study of the relationship between structure and reactivity of organic molecules.More specifically, physical organic chemistry applies the experimental tools of physical chemistry to the study of the structure of organic molecules and provides a theoretical framework that interprets how structure influences both mechanisms and rates of organic reactions.
Venn was born and raised in Toronto, Canada, where she completed her BSc in Physics & Astronomy at the University of Toronto in 1987. She then received her PhD in Astronomy from the University of Texas at Austin in 1994 working with Christopher Sneden and David L. Lambert on the evolution of massive stars, and pursued postdoctoral research at the Max Planck Institute for Astrophysics ...
Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. [1]
Rotary evaporation [7] is a common technique used in laboratories to concentrate or isolate a compound from solution. Many solvents are volatile and can easily be evaporated using rotary evaporation.