Homogeneous and heterogeneous mixtures settle, or separate. As a homogeneous mixture, a solution has one phase (liquid) although the solute and solvent can vary: for example, salt water. Air can be more specifically described as a gaseous solution (oxygen and other gases dissolved in the major component, nitrogen). Since interactions between molecules play almost no role, dilute gases form rather trivial solutions. In part of the literature, they are not even classified as solutions. In gas intermolecular space is greatest and intermolecular force of attraction is least. In chemistry, a mixture is a substance containing two or more elements or compounds that are not
Three-phase electric power normal use. A four-wire system with symmetrical voltages between phase and neutral is obtained when the neutral is connected to the "common star point" of all supply windings. In such a system, all three phases will have the same magnitude of voltage relative to the neutral. Other non-symmetrical systems have been used. The four-wire wye system is used when a mixture of single-phase and three-phase loads are to be served, such as mixed lighting and motor loads. An example of application is local distribution in Europe (and elsewhere), where each customer may be only fed from one phase and the