In this site we focused on the the areas of science incluod analytical chemisty, general chemistry, inorganic chemistry, organic chemistry, physical chemistry, and spectroscopy.(Online Chemistry Dictionary
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Methane, the principal component of natural gas, is shown represented in three formats, each of which provides different information about the components and 3D structure of the molecule.
Methane Representations
Tage: methane, structure, model, ball and stick, natural gas
The compound sodium chloride consists of Na+and Cl- ions held together by electrostatic forces of attraction in a very large ordered network called a crystal. The hypothetical combination of the one Na+ and one Cl- ion indicated is a formula unit. It is the smallest collection of ions from which we can deduce the formula NaCl.
Symbols & periodic table locations of some monatomic ions
In general, (a) the metals of Groups 1A and 2A and aluminum have just one cation, which carries a positive charge equal in magnitude to the A-group number; (b) the metals of the B-group have two or more cations of different charges, though in some cases only one of these cations is commonly encountered; and (c) the nonmetals of Groups 7A and 6A, nitrogen and phosphorus form anions with a charge equal to “ the group number minus eight.” l
Symbols & periodic table locations of some monatomic ions
Symbols & periodic table locations of some monatomic ions
Scheme based on the periodic table to assist in writing formulas
The lines trace a continuous path from boron (B) to fluorine (F). The element that is generally written first in the formula of a binary molecular compound is the one that is closer to the beginning of this path
Dalton assumed a combining ratio of hydrogen to oxygen atoms of 1:1. Data at the time suggested that the mass ratio of hydrogen to oxygen in water was 1:7. Taking the atomic weight of hydrogen to be one, that of oxygen was seven. Modern data indicate that the combining ratio of hydrogen to oxygen atoms is 2:1 and that the mass ratio is 1:8 (or 2:16). If the atomic weight of hydrogen is taken to be one, that of oxygen must be 16. see also: Dalton's theory and conservation of mass
Dalton's atomic weight problems
Tage:
the law of multiple proportions, Dalton, atomic mass, water, mass percent
Dalton's theory explained these two basic laws of the chemical combination as described in the text. If six fluorine and four hydrogen atoms are available before the reaction, the 10 atoms will still be present in the products, in this case, four HF molecules and one unreacted fluorine molecule.
Illustration of the Law of Definite Proportions Basic copper carbonate occurs in nature as the mineral malachite (a), it forms as a patina on copper roofs (b) and bronze statues, and can also be synthesized in the laboratory (c). Regardless of its source, basic copper carbonate has the same composition.
ChemDraw is the best chemistry software for students
ChemDraw and Sketcher are the drawing tool online of choice for creating publication-ready, scientifically. online chemical databases and viewing and publishing online structures
There are two types of ChemDoodle Web Sketchers, the Full Sketcher, and the Single Molecule Sketcher. You can choose either above in this demo. Based on the interface, you may be using one or the other or both. The Full Sketcher allows for the creation of multiple chemical structures, shapes, and figures. The Single Molecule Sketcher provides a streamlined interface for drawing a single molecular structure
The introduction tutorial to the ChemDoodle Web Sketcher
Precision and accuracy Comparing precision and accuracy: a dart board analogy The accuracy and precision of darts hitting a dart board illustrate the ways that data can be precise and/or accurate. (a) The darts are both scattered (low precision) and off-center (low accuracy). (b) The darts are in a tight cluster (high precision) but still off-center (low accuracy). (c) The darts are somewhat scattered (low precision) but evenly distributed about the center (high accuracy).
The thermometer on the left is marked in degrees Celsius and the one on the right in degrees Fahrenheit. The freezing point of water is at 0 ¡C and 32 ¡F; the boiling point is at 100 ¡C and 212 ¡F. Note that for an interval of 10 ¡C, the corresponding interval on the Fahrenheit scale is 18 ¡F. This gives rise to the factor 18/10 = 1.8 in the equations that relate the two scales.
