eutectic mixture

Examples of eutectic mixture in the following topics:

• Alloys

  • An alloy is a mixture or metallic solid solution composed of two or more elements.
  • An alloy is a mixture or metallic-solid solution composed of two or more elements.
  • Unlike pure metals, most alloys do not have a single melting point; rather, they have a melting range in which the substance is a mixture of solid and liquid.
  • However, for most alloys, there is one particular proportion of constituents, known as the "eutectic mixture," at which the alloy has a unique melting point.

• Crystalline Solids

  • The lowest mixture melting point, e, is called the eutectic point.
  • For example, if A is cinnamic acid, m.p. 137 ºC, and B is benzoic acid, m.p. 122 ºC, the eutectic point is 82 ºC.
  • Above this temperature the mixture is either a liquid or a liquid solid mixture, the composition of which varies.
  • Melting or freezing takes place over a broad temperature range and there is no true eutectic point.
  • One such mixture consists of α-naphthol, m.p. 94 ºC, and p-toluidine, m.p. 43 ºC.

• Substances and Mixtures

  • A homogeneous mixture is a mixture of two or more chemical substances (elements or compounds), where the different components cannot be visually distinguished.
  • Often separating the components of a homogeneous mixture is more challenging than separating the components of a heterogeneous mixture.
  • In practical terms, if the property of interest is the same regardless of how much of the mixture is taken, the mixture is homogeneous.
  • Mixtures are described as heterogeneous or homogeneous.
  • This mineral deposit is composed of a mixture of substances.

• Dalton's Law of Partial Pressure

  • In fact, it was with a gas mixture—ordinary air—that Boyle, Gay-Lussac, and Charles performed their early experiments.
  • The mole fraction is a way of expressing the relative proportion of one particular gas within a mixture of gases.
  • We do this by dividing the number of moles of a particular gas i by the total number of moles in the mixture:
  • The partial pressure of one individual gas within the overall mixtures, pi, can be expressed as follows:
  • A mixture of 2 mol H2 and 3 mol He exerts a total pressure of 3 atm.

• Mole Fraction and Mole Percent

  • Mole fraction is the number of molecules of a given component in a mixture divided by the total number of moles in the mixture.
  • In a mixture of ideal gases, the mole fraction can be expressed as the ratio of partial pressure to total pressure of the mixture.
  • A mixture of gases was formed by combining 6.3 moles of O2 and 5.6 moles of N2.
  • What is the mole fraction of nitrogen in the mixture?
  • What is the mole fraction of hexane in this mixture?

• Resolution of Racemates

  • As noted earlier, chiral compounds synthesized from achiral starting materials and reagents are generally racemic (i.e. a 50:50 mixture of enantiomers).
  • Reaction of a racemate with an enantiomerically pure chiral reagent gives a mixture of diastereomers, which can be separated.
  • The following diagram illustrates this general principle by showing how a nut having a right-handed thread (R) could serve as a "reagent" to discriminate and separate a mixture of right- and left-handed bolts of identical size and weight.

• Stereogenic Nitrogen

  • It rapidly inverts its configuration (equilibrium arrows) by passing through a planar, sp2-hybridized transition state, leading to a mixture of interconverting R and S configurations.
  • If the nitrogen atom were the only chiral center in the molecule, a 50:50 (racemic) mixture of R and S configurations would exist at equilibrium.
  • If other chiral centers are present, as in the ephedrin isomers, a mixture of diastereomers will result.

• Heterogeneous Catalysis

  • Heterogeneous catalysis is a type of catalysis in which the catalyst occupies a different phase than the reaction mixture.
  • Homogeneous catalysts are those that occupy the same phase as the reaction mixture (typically liquid or gas), while heterogeneous catalysts occupy a different phase.
  • Generally, heterogeneous catalysts are solid compounds that are added to liquid or gas reaction mixtures.
  • For one, heterogeneous catalysts can be separated from a reaction mixture in a straightforward manner, such as by filtration.

• Gas Requirements

  • Cells are grown and maintained at an appropriate temperature and gas mixture of oxygen, carbon dioxide, and nitrogen in a cell incubator.
  • Cells are grown and maintained at an appropriate temperature and gas mixture (typically, 37°C and a mixture of oxygen, carbon dioxide, and nitrogen) in a cell incubator .
  • Cells are grown and maintained at an appropriate temperature and gas mixture of oxygen, carbon dioxide, and nitrogen in a cell incubator.

• Encaustic

  • Encaustic painting involves painting with a mixture of heated beeswax to which colored pigments have been added.
  • Encaustic painting, also known as hot wax painting, involves painting with a mixture of heated beeswax to which colored pigments have been added.
  • First, the beeswax mixture is heated; once it is melted, various pigments are added to create the color palette.
  • The simplest encaustic mixture can be made from adding pigments to beeswax, but there are numerous recipes that can be used, such as other types of waxes, damar resin, or linseed oil.