The Mole Tutorial This tutorial introduces the concept of the mole and how it is used in chemistry to connect macroscopic and molecular level scales. Practice is provided on the applied definition of the mole. Significant Figures Tutorial This tutorial provides a brief review of the guides for determining how many significant figures to include when reporting your answer in a chemistry calculation.
In patristic Greek, the word Stoichiometria was used by Nicephorus to refer to the number of line counts of the canonical New Testament and some of the Apocrypha.
Definition[ edit ] A stoichiometric amount  or stoichiometric ratio of a reagent is the optimum amount or ratio where, assuming that the reaction proceeds to completion: All of the reagent is consumed There is no deficiency of the reagent There is no excess of the reagent.
Stoichiometry rests upon the very basic laws that help to understand it better, i. In general, chemical reactions combine in definite ratios of chemicals. Since chemical reactions can neither create nor destroy matter, nor transmute one element into another, the amount of each element must be the same throughout the overall reaction.
For example, the number of atoms of a given element X on the reactant side must equal the number of atoms of that element on the product side, whether or not all of those atoms are actually involved in a reaction. Chemical reactions, as macroscopic unit operations, consist of simply a very large number of elementary reactionswhere a single molecule reacts with another molecule.
As the reacting molecules or moieties consist of a definite set of atoms in an integer ratio, the ratio between reactants in a complete reaction is also in integer ratio.
A reaction may consume more than one molecule, and the stoichiometric number counts this number, defined as positive for products added and negative for reactants removed. Thus, to calculate the stoichiometry by mass, the number of molecules required for each reactant is expressed in moles and multiplied by the molar mass of each to give the mass of each reactant per mole of reaction.
The mass ratios can be calculated by dividing each by the total in the whole reaction. Elements in their natural state are mixtures of isotopes of differing mass, thus atomic masses and thus molar masses are not exactly integers.
For instance, instead of an exact A stoichiometric reactant is a reactant that is consumed in a reaction, as opposed to a catalytic reactantwhich is not consumed in the overall reaction because it reacts in one step and is regenerated in another step.
Converting grams to moles[ edit ] Stoichiometry is not only used to balance chemical equations but also used in conversions, i.
For example, to find the amount of NaCl sodium chloride in 2.Create your own math worksheets. Linear Algebra: Introduction to matrices; Matrix multiplication (part 1) Matrix multiplication (part 2).
B. Bearing Corrosion - chemical attack on bearing metal or on one of the metals in a bearing alloy caused by acids evolved during chemical deterioration of the oil. The acids may be mild organic acids from the oil itself or, more likely, the strong acids that result from breakdown of nitrogen or sulfur compounds, which can enter the oil from several sources.
The 'lampbrush' phase of extended chromosomes during meiosis has also been suggested to enable forms of genetic re-processing.
In non-mammals this extended phase involves open transcription of coding and non-coding regions and has been proposed to be a form of genetic processing (Wolfe R), which probably occurs in a less obvious way in mammals as well. In chemistry the mole is a fundamental unit in the Système International d'Unités, the SI system, and it is used to measure the amount of substance.
The gelling of waxy crudes and the deposition of wax on the inner walls of subsea crude oil pipelines present a costly problem in the production and transportation of oil.
As explained on pages –, other heat sources are generating heat within the earth, so these thicknesses of granite would be even initiativeblog.com granite crust is generally estimated to be at least 50 km (30 miles) thick.
Therefore, steady state has not been reached.