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The side-on design is used, for instance, in the type 931, the first mass-produced PMT. Besides the different photocathode materials, performance is also affected by the transmission of the window material that the light passes through, and by the arrangement of the dynodes. Many photomultiplier models are available having various combinations ...
Starting from 2024, STEP will be administered by OCR, replacing CAAT, who was responsible for administering STEP in previous years. Being after the reply date for universities in the UK, [1] STEP is typically taken as part of a conditional offer for an undergraduate place. There are also a small number of candidates who sit STEP as a challenge.
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.
Valence shell electron pair repulsion (VSEPR) theory (/ ˈ v ɛ s p ər, v ə ˈ s ɛ p ər / VESP-ər, [1]: 410 və-SEP-ər [2]) is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. [3]
In modern chemistry, a chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes other symbols, such as parentheses, brackets, and plus (+) and minus (−) signs. [9]
Conversion and its related terms yield and selectivity are important terms in chemical reaction engineering.They are described as ratios of how much of a reactant has reacted (X — conversion, normally between zero and one), how much of a desired product was formed (Y — yield, normally also between zero and one) and how much desired product was formed in ratio to the undesired product(s) (S ...
The suffix-oate is the IUPAC nomenclature used in organic chemistry to form names of compounds formed with ester. They are of two types: They are of two types: Formed by replacing the hydrogen atom in the –COOH by some other radical , usually an alkyl or aryl radical forming an ester .
Polymethylpentene melts at ≈ 235 °C. It has a relatively low density (0.84 g/cm 3) among plastics and is transparent.It has low moisture absorption, and exceptional acoustical and electrical properties.