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What’s The Difference Between A Mole Fraction And PPM? How Do You Convert Them? (Explained)

What’s The Difference Between A Mole Fraction And PPM? How Do You Convert Them? (Explained)

The concentration of a solution can be quantified in a number of different ways. For processes that take place in solutions, molarity, for instance, can be used to define solution concentrations.

Mole fractions are used to calculate the vapor pressures of mixes of comparable liquids as well as to describe gas concentrations.

A mole fraction is a measurement of concentration that is equal to the product of the moles of a component and the total moles of the solution. Due to the fact that it denotes a ratio, the term “mole fraction” is unitless. When all the parts of a solution’s mole fraction are added up, they equal one.

PPM is measured in milligrams per liter (mg/L) by chemists. The mass of a chemical or contamination per volume of a liquid solution is the unit of measurement here. On a lab report, ppm or mg/L both mean the same thing.

PPM stands for parts per million or one (g, mole, atom, etc.) of solute in the solution. Between 0 and 1, the mole fraction is unitless and simply measures mole/mole.

Let’s find out their differences!

What Is A Mole Fraction?

Calculating mole fraction
Mole fraction is a measurement of the concentration.

A mole part is called a unit of measure for the amount of solution, which is used in chemistry to represent the number of moles of a chemical liquid. It contains atoms, molecules, ions, and electrons in 12 grams of carbon.

The mole fraction of liquid in a solvent is simply the number of moles of solvent divided by all the moles of the solution, which equals one. If the mole fraction is 1 without a unit, it is called an expression.

What Is A PPM?

PPM means parts per million. PPM is used to measure the concentration of a pollutant in units of mass. PPM is a percentage by weight. 1% w.w. means 1 gram of substance per 100 grams of sample. Chemists express ppm as milligrams per liter (mg/L).

Other similar abbreviations mean:

  • PPM (parts per million 106)
  • PPB (parts per billion 109)
  • PPT (parts per trillion 1013)
  • PPQ (parts per quadrillion)

PPQ is largely considered a theoretical construct rather than a measurement and is surprisingly little used.

Distinguish Between Mole Fraction And PPM

As we have read earlier, mole fraction and ppm are two units of measurement. The difference between them is that the mole fraction is equal to the number of solute molecules and atomic mass, while ppm represents the number of solute molecules in a solution. 

CharacteristicsMole FractionPPM
Concentrations unitsThe total number of mole fractions of a substance is the sum of all its atoms. This is sometimes helpful in dealing with Pv=nRT. Also, the sum of the mole fractions of each substance in a solution is equal to one.The PPM measurement is the amount of contaminated or chemically treated water per unit volume.
VolumeMole fraction equals volume fraction. When all gases are measured at the same temperature and pressure, they all have the same mole fraction.If we express PPM as a volume in units of water and volume in particles, the volume of ppm becomes equal to H1/1.
ValueThe mole fraction is divided by the number of moles for the total number of molecules, so the value of the mole fraction is always one or less than one.The value of PPM is equal to one, which represents 1/1000000 whole number units
FormulaThe mole fraction is always denoted by x if the solution contains a and b, then the mole fraction formula is:
Mole fraction of solute=
moles of solute
Moles of solute + moles of solute= nA
Here is the formula for PPM
ppm= 1/1,000,000 = 0.0001
Comparison Table: Moele Fraction and PPM

Conversion Between Them

PPM Conversion

Both of them are difficult to replace. Using percentages can convert ppm; for example, one percent is “per hundred,” so to convert one percent to ppm, multiply one hundred by four (104).

In simple terms, this means that you multiply the percentage value by 10,000 to get the ppm value. You can also use this method to convert ppm. One ppm is 1 mg/L; find the molar mass of the solution in the periodic table of chemistry.

For example, find the PPM of chloride ions in a NaCl 0.1 M solution. The molar mass in a liquid of 1 M of sodium chloride is 34.45.

And looking at the atomic mass of chlorine on the periodic table shows that only cl1 ions are found in NaCl, which is insufficient. Because of this work, we are looking for only chloride ions in the solution.

Now, we only have 34.45 g/mole or 35.5 g/mole. Multiply this value by 0.1 in a 0.1M solution to get the number of grams, and after multiplying, you get 35.5 grams per liter for a 0.1 solution.

3550 mg/liter is equal to 3.55 grams/liter. Since one milligram/liter is one ppm, the NaCl solution contains 3550 chlorine PPM ions.

Mole Conversion
Mole Conversion

Mole Conversion

First, convert grams of solvent and solute to moles of both. Then divide the moles of solute by the moles of substances in the solution. Calculate the mole fraction after division, such as moles of solute per liter of solution.

Mole Fraction Example

Here we dissolve 77 g of carbon tetrachloride in 78 g of acetone, so what will be its mole fraction?

First, you need to find the atomic masses of both elements from the periodic table of chemistry and convert the masses of both compounds into the number of moles.

The atomic mass of carbon is found to be AMU 12.0 and that of chlorine is 35.5. So, 1 mole of carbon tetrachloride is 154 grams. and you have 77 grams of carbon tetrachloride which = 77/154 = 0.5 mole is formed.

The atom mass of hydrogen is AMU 1 and that of oxygen is AMU 16. The molar mass of acetone is 58 grams and you have 78 grams of acetone, which is 1.34 moles.

This means that the total number of moles in the solution is 1.84. Now, we can calculate the exact amount of solution using the mole fraction.

Mole fraction of tetrachloride:

0.5 moles

1.84 mole = 0.27

Mole fraction of acetone:  

1.34 moles

1.84 moles= 0.73

The periodic table of elements
The periodic table of elements

What Is The Mole Fraction Symbol?

Most people consider the mole symbol and the mask to be the same, which is wrong. The abbreviation for the mole is “mol,” while the symbol for a mole is “χ,” it is the Greek “χ instead of the Roman x. It is used in many chemistry equations.

Mole fraction=  χ1=n1ntot

How Do You Find A Mole Fraction Of Gas?

If you need to find the mole fraction of a substance and you know the total number of mole parts in a mixture of the required component, you can find it by taking the ratio of the number of mole parts of all the components of that substance.

The mole fraction of any gas molecule is the ratio of the total number of moles of all substances present. But if you don’t know the total number of moles and you know the partial pressure, you can find the partial pressure of the desired gas by multiplying the total pressure.

Looking at the partial pressure of a gas, we will talk about the mole fraction of the gas. Partial pressure means the individual pressures that are the product of the mole fraction due to the total pressure of the gas.

What Is PPM In Water?

As discussed above, PPM refers to the amount of contaminated or chemically contaminated water per unit volume, so PPM is also called the unit of water.

How much chlorine, calcium, and total alkalinity are included? A PPM means that the total amount of water in a substance is one-millionth of a PPM.

(moles/Liter = M)  
Parts Per Million
1 M35.535,50035,500
10-1 M3.553,5503,550
10-2 M0.355355.0355.0
10-3 M0.035535.535.5
10-4 M0.003553.553.55
Moles in PPM

What Is The Partial Fraction In Mole Fraction?

The mole fraction of a given gas is the partial pressure of that gas multiplied by the mole fraction of the mixture.

How Do You Find Partial Pressure From Moles?

There are two ways to find the partial pressure, which are as follows:

  • Use Pv=nRT to calculate the individual pressures of each gas in the mixture.
  • Using the mole fraction of each gas, calculate the percentage of pressure given by the total pressure given by each gas.

How Is Dalton’s Law Of Partial Pressures Related To Mole Fraction And Partial Pressure Of Gases In A Mixture?

According to Dalton’s law of partial pressure, the pressure exerted by a mixture of a solution of a non-reactive gas is equal to the sum of the partial pressures of each component gas. Partial pressure is defined as the pressure of all the gases in a mixture if they are at the same temperature.

The mole fraction within a mixture of gases is a way of expressing the ratio of nearby gases. In a mixture, when the partial pressure is exerted by a gas, it is directly proportional to its mole fraction.

Does Mole Fraction And PPM Depend On Temperature?

Concentrations like mole fraction, ppm, or mass percentage do not change with temperature.

The mole fraction consists of the mass of the solute and the solvent, and the temperature does not affect the mass because the mass does not change. Therefore, the mole fraction does not depend on temperature.

Let’s watch this video and learn about the mole concept, mole fraction, PPM, and PPB calculations.


  • The mole fraction is less than one. 
  • One ppm is equal to one gram per liter of water.
  • The partial pressure of each gas is equal to its mole fraction in the mixture of gases. If the partial pressure of a gas is changed in a mixture, the mole fraction must also be changed.
  • PPM is the unit used to measure the amount of solution in gases.

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