Molar

Molar may refer to:

See also:

Molar concentration

Molar concentration, also called molarity, amount concentration or substance concentration, is a measure of the concentration of a solute in a solution, or of any chemical species, in terms of amount of substance in a given volume. A commonly used unit for molar concentration used in chemistry is mol/L. A solution of concentration 1 mol/L is also denoted as 1 molar (1 M).

Definition

Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. For use in broader applications, it is defined as amount of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase c:

Here, n is the amount of the solute in moles,N is the number of molecules present in the volume V (in litres), the ratio N/V is the number concentration C, and N_A is the Avogadro constant, approximately 6.022×10²³mol⁻¹.
Or more simply: 1 molar = 1 M = 1 mole/litre.

In thermodynamics the use of molar concentration is often not convenient, because the volume of most solutions slightly depends on temperature due to thermal expansion. This problem is usually resolved by introducing temperature correction factors, or by using a temperature-independent measure of concentration such as molality.

Molar (tooth)

The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name molar derives from Latin, molaris dens, meaning "millstone tooth", from "mola", millstone and dens, tooth. Molars show a great deal of diversity in size and shape across mammal groups.

Human anatomy

In humans, the molar teeth have either four or five cusps. Adult humans have twelve molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of twenty, although this varies from individual to individual. Ethnicity can also have an impact on the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all.

The human mouth contains upper (maxillary) and lower (mandibular) molars. They are: maxillary first molar, maxillary second molar, maxillary third molar, mandibular first molar, mandibular second molar, and mandibular third molar.