Chemical Laws

Name:
Chemical Laws
Detailed information:
A group of basic principles governing the combining power and reaction characteristics of elements. Among the more important are:(1) Law of mass action: the rate of a homogeneous (uniform) chemical reaction at constant temperature is proportional to the concentration of the reacting substances.(2) Law of definite or constant composition: any chemical compound contains the same elements in the same fixed proportions by weight. Exceptions to this law occur in solid compounds, such as silicates, that are known as nonstoichiometric compounds.(3) Law of multiple proportions: when two elements unite to form two or more compounds (e.g., nitrogen and oxygen can form five different oxides), the weight of one element that combines with a given weight of the other is in the ratio of small whole numbers. Hydrogen and oxygen unite in the ratio of 1 to 8 in water and of 1 to 16 in hydrogen peroxide. Thus, the weights of oxygen that unite with 1 g of hydrogen are in the ratio of 1 to 8.(4) Law of conservation of mass: any chemical reaction between two or more elements or compounds leaves the total mass unchanged, the reaction products having exactly the same mass as present in the reactants, regardless of the extent to which other properties are changed.(5) Law of Avogadro: equal volumes of gases at constant temperature and pressure contain the same number of molecules whether the gases are the same or different. 22.4 L of any gas contains 6.02 × 10²³ molecules. See Avogadro's Law; Mole.