Mixture

Under a mixture ( mixture ) is defined as a substance that consists of at least two pure substances. A mixture of two components is (sometimes also binary system ) called binary mixture, mixtures of three components ternary mixture.

From a mixture are usually meant for granules ( heap, bulk ) or living components ( seeds), the mix only with each other but can not mix homogeneously, without dying or becoming inoperable.

In some contexts it is called a conglomerate.

• 3.1 macro -mixing and micro-mixing

Types of mixtures

On the degree of mixing

Basically mixtures fall into two groups:

• Homogeneous mixtures are mixed at the molecular level pure substances. Homogeneous mixtures are monophasic.
• Heterogeneous mixtures are not finished mixed as the pure substances are present in clearly defined phases. Heterogenous mixtures ( dispersions) are multiphase.

Colloids are an intermediate form of homogeneous and heterogeneous mixtures. In these liquids solids are mixed, however, occur in very small periods of a few molecules and therefore similar solutions ( homogeneous) behave.

After the state of aggregation of the mixed substances

In the mixing of two substances in three possible states of matter arise nine combinations, which still partially different forms occur (red = homogeneous, yellow = heterogeneous):

After the physical state of the mixture

Homogeneous mixtures, but also some heterogeneous mixtures have a certain physical state (solid, liquid or gaseous). For example, solutions generally fluent ( regardless of whether the dissolved substance in the solvent before mixing solid, liquid or gaseous form was ).

• Examples of solid mixtures in nature are dolomite and granite. Granite is a mixture of quartz, feldspar, mica and hornblende.

• An example of liquid mixtures in nature is lava. A Molotov cocktail is an artificial liquid mixture of gasoline and white phosphorus. In the beverage industry is often called blended beverage mixes.

• The most common gaseous mixture is air. This gas mixture consists of nitrogen and oxygen, among other things.

Physical chemistry

In the mixture, the starting materials are included unchanged. The starting materials are often unrecognizable, because the mixture other physical properties than any isolated starting material. When mixing, usually there is no new substance. So cement is initially a mixture but changed chemically by addition of water. The specific properties such as density, boiling point, or color are the mixing ratio (by mass) of components dependent.

If you want to mixtures separated into their pure substances, one takes advantage of the different physical properties. This results in selection of the separation method.

Process engineering

Macro -mixing and micro-mixing

In the chemical reaction engineering differentiates the state of mixing of the reaction mixture in a reactor:

• Macromixing: that's all what you ' could be seen with the naked eye ', the macro mixing in the reactor is characterized by the residence time distribution, which can be experimentally obtained by ' tracer measurements ' for example.
• Micro-mixing: this is a characteristic of the fluid: complete micro-mixing = molecularly fluid (for example, saline)
• Complete ' non- micro-mixing ' = complete segregation = fluid with a dispersion of microscopic closed fluid elements (example: Milk / emulsion).

In English, and also in some German schools the term definition is slightly different: engl. macromixing and macro fluid = segregiertes fluid; micromixing and microFLUID = molecularly fluid. For the term ' macro- mixing ', as defined in the present, is then ' Contacting pattern ' is used.

Maßbegriffe of mixtures

Proportion, concentration or content of the material content of a substance in a mixture in terms of mass, volume or amount of substance:

• Mass fraction, volume fraction, mole fraction
• Volume concentration, mass concentration, molar concentration
• Molality

Concrete examples:

• Salinity, salinity

Term is defined in the legislation

In the legislation on hazardous substances law, the terms " mixture " and " substance " is defined differently than in the above chart shows: The legislature used "stuff" only for what is declared in the schema as " pure substance " (element or compound) and not as a generic term for everything. The term " mixture " ( specified by the legislature earlier preparation) is inversely not a subset of cloth, but a parallel term to do so. So is true for the introduction of the GHS for " substances", another term for as "mixtures"; this is not possible with the definition given in the article.