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The most serious disadvantage is the limited types of knowledge that can be assessed by multiple choice tests. Multiple choice tests are best adapted for testing well-defined or lower-order skills. Problem-solving and higher-order reasoning skills are better assessed through short-answer and essay tests.
Chemical classification systems attempt to classify elements or compounds according to certain chemical functional or structural properties. Whereas the structural properties are largely intrinsic, functional properties and the derived classifications depend to a certain degree on the type of chemical interaction partners on which the function is exerted.
A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken or new bonds formed or both. There are four major types of compounds, distinguished by how the constituent atoms are bonded together.
IARC group 3 substances, chemical mixtures and exposure circumstances are those that can not be classified in regard to their carcinogenicity to humans by the International Agency for Research on Cancer (IARC).
In organic chemistry, an acetyl group is a functional group denoted by the chemical formula −COCH 3 and the structure −C(=O)−CH 3. It is sometimes represented by the symbol Ac [5] [6] (not to be confused with the element actinium). In IUPAC nomenclature, an acetyl group is called an ethanoyl group.
An ionic compound is named by its cation followed by its anion. See polyatomic ion for a list of possible ions. For cations that take on multiple charges, the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO 3) 2 is copper(II) nitrate, because the charge of two nitrate ions (NO −
Although most compounds are referred to by their IUPAC systematic names (following IUPAC nomenclature), ... Other fluorides: AlF 3, AmF 3, NH 4 F, NH 4 HF 2, ...
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. [ 1 ] : 620 Hydrocarbons are examples of group 14 hydrides . Hydrocarbons are generally colourless and hydrophobic ; their odor is usually faint, and may be similar to that of gasoline or lighter fluid .