1 December 2023

In chemistry there are various terms that are an important part of it and are considered tools of great contribution to science. One of these terms is the percentage of volume, which is a measurement used, generally, in the chemical and industrial area to express quantities of a substance in a liquid solution.

On the other hand, the percentage of volume is very useful in the manufacturing, production, quality control and analysis of products or substances. In this way, it is known as a fundamental measure in different areas, therefore, throughout this article we will explain a little more about the volume percentage.

## Definition of percentage by volume in chemistry

In chemistry, it is understood as percentage by volume, which is a measure of concentration that a substance possesses in a liquid solution, this expressed as “% vol” or V/v. Unlike mass percentage, which expresses the total mass of the solution, volume percentage expresses the volume occupied by a liquid substance, such as water.

The percentage by volume is directly related to the solubility of a compound, since this represents the the ability of one substance to dissolve in another.

This term represents the percentage of the parts of the total volume of a solution that occupies a substance This means that the percentage by volume is defined as the amount of volume of a certain substance present in a solution, which is divided by the total volume of the solution multiplied by 100.

Typically, this measure is used to describe the amount of a component in a liquid solution, an example of this would be the percentage of alcohol in an alcoholic drink. In this sense, the volume percentage is important in areas such as manufacturing, quality control and chemical analysis of a product.

In addition, it is considered a vital tool and fundamental in various fields of science and even technology.

## What is the formula for percent by volume? – calculation

To calculate the percentage by volume of a substance, formulas are used that help to have theoretical and precise results. Likewise, the mathematical formula to calculate it is the following: % vol = (Volume of the substance / Total volume of the solution) x 100%.

From this formula it is known that “Volume of the substance” is the specific volume of the substance that is in the solution. Whereas, “Total volume of solution” deals with the total volume of a solution which includes both the volume of the substance and the volume of the solvent used to dilute it.

In general, this formula is used to express the concentration of a solute in a liquid solvent when speaking in terms of its volume.

For example, if we have a solution containing 250 ml (milliliters) of ethanol diluted in a total of 1000 ml (1 liter) of solution. To obtain the percentage by volume of ethanol, the formula would be as follows: % vol ethanol = (250 ml / 1000 ml) x 100% = 25% vol.

This means that, the 25% of the total volume of the solution is occupied by ethanol. In this way it is obtained that ethanol occupies 25% of the volume of the liter of solution used.

## When was the expression percentage by volume developed and why?

The measure of percent by volume It was developed at the beginning of the 20th century. as a way to measure the concentration of a substance within a liquid solution more accurately and easily. Although an exact date of its development cannot be established, it is known that, in general, its use began in the chemical industry and in the production of alcoholic beverages in the 1920s.

Before the creation of this expression, chemists used different measurements to describe the concentration of substances in liquid solutions. Among these measures are the expressions or measures of molarity, molality and weight percent.

Despite this, these measures were not adequate when it was necessary to describe the concentration of substances in liquid solutions in a precise way. One of the industries most interested in finding the formula to calculate the volume percentage was alcoholic, since the concentration of alcohol in these drinks is a critical factor.

In this way, the percentage by volume was converted into a standard measurement when calculating the concentration of substances in liquid solutions, all thanks to its simplicity and precision. Over time, this has become a fundamental measure in various fields, including chemistry, industry and science in general.