Search results
Results from the WOW.Com Content Network
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.
The numbers 200-900 would be confused easily with 22 to 29 if they were used in chemistry. khīlioi = 1000, diskhīlioi = 2000, triskhīlioi = 3000, etc. 13 to 19 are formed by starting with the Greek word for the number of ones, followed by και (the Greek word for 'and'), followed by δέκα (the Greek word for 'ten').
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.
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.
In chemistry, the law of multiple proportions states that in compounds which contain two particular chemical elements, the amount of Element A per measure of Element B will differ across these compounds by ratios of small whole numbers. For instance, the ratio of the hydrogen content in methane (CH 4) and ethane (C 2 H 6) per measure of carbon ...
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 −
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 .