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Percent by Weight Formula

Last updated date: 18th Apr 2024
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Solutions and Percent Weight Change Formula

There are various features of solutions, including molarity, normality, molality, and percent by weight formula. Representation of solutions as a relative percentage concentration of solute in the given solution is one of the most popular and preferred methods, and it has various benefits. A solute is a minor component of the solution dissolved in solvent (the major part). The solute composition and the solution's composition are required to calculate the percentage by weight formula.

Percent Weight Change Formula 

Here are some ways in which the percent weight change formula is represented:


We express a solution's volume concentration as %v/v, also known as volume per volume; here, both solute and solvent in a solution are in liquid form. For example, 50ml sulphuric acid getting diluted in 50ml water is represented as sulphuric acid 50% v/v.


This percent by weight formula represents any solution expressed as %w/w, meaning weight by weight; here, we only consider the weight of any solution's components. For example: if a 100g solution contains 30g HCl and 70g water, we express it as hydrochloric acid 30% w/w.


This percentage weight by volume formula is expressed as %w/v, meaning weight per volume, also known as m/v. For example: if we use 1g Potassium Iodide for making 100ml solution, it is represented as 1%w/v solution of KI.

Defining Solution

A solution refers to a homogeneous mixture of two or many compounds with a particle size is less than 1nm. 

Characteristics of a Solution 

The characteristics of a solution are as follows: 

  • It is a homogenous mixture of two or more given substances. 

  • It does not let the beams of light scatter. 

  • A solution tends to be stable. 

  • It tends to be composed of only one specific phase. 

  • The particles of a solute that are present in the given solution are not possible to be viewed by the naked eye. 

  • It is not possible to separate the solute from a given solution with the help of filtration. 

Common Ways of Describing the Solution

Solutions are commonly described in various ways, which are as follows:

  • Molarity – It means the number of moles of substance per liter in the solution.

  • Normality – It is the number of gram equivalents per liter volume of the solution.

  • Molality – Molality is the number of solute moles per Kg of solution.

Percentage Concentration of Solute in any Solution (percentage weight by volume formula)

The mass of solute in per ml volume of solution * 100. It is represented as follows:

(Mass of Solute(g) / Volume of Solution(ml) ) *100

What is Solubility? 

Solubility is generally referred to as the ability of one particular compound to dissolve in another given compound. If a given liquid can completely dissolve in another liquid, then both those liquids are said to be miscible. And two given substances that are never able to form a solution by mixing or dissolving are referred to as immiscible. 

Solubility tends to depend majorly on the composition of a solute and solvent as well as on the temperature and pressure. And the extent of the solubility of a given substance in a specific condition is usually measured as the concentration of the given solute in a saturated solution (the type wherein it is not possible to dissolve any more solute). 

Factors that Affect Solubility 

  • Temperature tends to affect the solubility of both solids as well as gases. 

  • Pressure tends to affect the solubility of only gases. 

  • Polarity: solutes are known to dissolve more easily in solvents that tend to have a similar polarity. 

  • Molecular size. 

  • Stirring is also known to increase the speed of dissolving. 

What is a Solute? 

A solute is basically defined as the substance that is dissolved in a given solution. A solute can either be in the form of a solid, a liquid, or that of a gas. 

What is a Solvent? 

The liquid in which other materials tend to dissolve to form a solution is commonly known as the solvent. A solvent can be acidic, basic, amphoteric, or neither. 

There are primarily three main types of solvents and they are as follows: 

  • Oxygenated solvents

  • Hydrocarbon solvents 

  • Halogenated solvents 

Differentiate between a Solute and a Solvent in a Solution 

The difference between a solute and a solvent in a solution is as follows: 



This is referred to as the substance that tends to get dissolved in a solution. 

This is referred to as the dissolving medium with regard to the solution. 

It can be found in various conditions including those of solids, liquids, as well as gases. 

It is mainly found in the state of a liquid, however, it can also be found in a gaseous state. A solvent is never found in a solid state. 

It has a boiling point higher than that of the solvent. 

It has a boiling point lower than that of the solute. 

The solubility of a given substance mainly tends to depend on the properties or characteristics of the solute. 

The solubility of a given substance mainly tends to depend on the properties or characteristics of the solvent. 


We represent all of the percentage types by making some slight changes to the standard method of calculating percent weight by volume, i.e., (solute's mass (g) / Solution volume (ml) ) *100. For calculating percent weight by weight, we take both numerator and denominator by their weight, and for calculating percent volume by volume, both are taken by their volumes.

FAQs on Percent by Weight Formula

1. Define solute and solvent in a solution.

A solute is a component that is in a lower quantity and is dissolved in the solvent. A solvent is in higher quantity which is used for dissolving the solute for a solution's formation. To know more check out the Percentage by Weight Formula article on Vedantu!

For example: in the solution of tincture of Iodine (Iodine mixture in alcohol), Iodine is the solute, and alcohol is the solvent.

2. What are the ways to represent the percent weight change formula?

Percent weight change formula can be represented using the following methods:

  • %v/v - In this method, only volumes of solute and solution are considered

  • %w/w - In this method, only weights of solute and solution are considered

  • %w/v - In this method, the weight of the solute is considered whereas the volume of the solution is considered.

3. Mention the most common ways for describing a solution.

We can describe a solution in terms of its components by calculating the following:

  • Molarity

  • Normality

  • Molality

  • Percent by weight: %v/v, %w/w, %w/v