Concentration’ is a basic term used in chemistry. In simple words, concentration is the measure of the quantity of a given substance when mixed or combined with another substance. The term is generally used for solutions, where it predicts the amount of solute dissolved in a given solvent. Concentration is the amount of solute present in one litre of solution. It is indicated by the letter C or S. We all know that a solution is made up of two components that are solute and solvent. When the amount of solute is more, then the solution is said to be a concentrated solution and when the amount of solute is less then the solution is said to be a diluted solution. To measure the amount of solute or solvent dissolved in the solution we use few terms that determine the concentration of the solution. In this article, we will focus on the different terms used to measure the concentration of a solution.
Molarity
The term molarity for a provided solution is described as the total number of moles of solute per litre of solution. The molarity of the solution depends on a few physical factors such as pressure and temperature, mass. Also, due to these factors, the volume of the system varies due to the change in physical conditions of the system. The molarity of the solution is denoted by the symbol M which is called molar. One molar of a solution is defined as the molarity of a solution where one gram of solute is dissolved in one litre of solution. The unit to express molarity is mol/L.Molarity is dependent on the number of moles whereas osmolarity is dependent on the number of osmoles. It is described as the number of osmoles of solute per litre (L) of a solution.
Molality
The expression molality is also in context with the concentration of the solution. The term molality (m) is interpreted as the number of moles of solute per kilogram of solvent. In the SI unit molality is expressed as moles per kilogram (mol/kg). The molality of a solution depends on the factors such as the mass of the solvent, temperature and pressure of the solvent. One molal of a solution is defined as the solution that contains one mole of solute in 1000g of solvent. Molality cannot be applied to impure substances or substances that are not pure.
Normality
Normality is the most common term used to measure the concentration of the solution. As per the definition, the number of gram or mole equivalents of solute present in one litre of a solution is called the normality of a solution. Normality is denoted by the letter N. The units used to express normalities are eq L-1 or meq L-1. The factors affecting the normality of a solution are the number of moles of solute and the volume of the solvent. Solvent meaning the substance (majorly in liquid state) that dissolves another substance to form a solution. The normality is majorly used in laboratories to prepare various solutions with different concentrations to estimate the volume of a solution.
Formality
The term formality also aids in determining the concentration of the solution. The formality of a solution can be described as the quantity or number of gram formula masses of the ionic solute that is dissolved per litre of the solution. The symbol used to denote formality is F. The concentration term formality is used for the ionic solids that are not represented as molecules but as a collection of ions. One formal of a solution is explained as one gram formula mass of solute per litre of the solution. Temperature is the main factor that affects the formality of the solution.
The concentration of the solutions is determined by quantitative and qualitative analysis. In general terms, we describe solution concentration as a measure of the quantity of solute that has been dissolved in a specific amount of solvent or solution. The different notations used for determining the concentration of solvent or solution helps in performing various calculations and experiments in laboratories. The exact amount of solute and solvent that has to be added can be known only in these concentration terms. The concentration of a solution plays a crucial role in chemistry and helps to determine the properties of the substance.
