Our mole fraction calculator is an online tool for the calculation of the mole fraction of a solution. It is a fast and user-friendly tool. The mole fraction of a solution is calculated to estimate the concentration of a solution. As we know that a solution is a mixture of solute and solvent. And there may be more than one solute present in a solution. The mole fraction of each solute is calculated separately.
What is a mole fraction?
It is the ratio of the number of moles of a solute to the number of moles of the solution. It is denoted by X. There is no SI unit for mole fraction. It tells about the concentration of the solution. Mole percent (n / n %) is calculated by multiplying the mole fraction by 100.
Steps to use mole fraction calculator
Follow these simple steps to use the calculator.
- Enter the number of moles of solute.
- Enter the number of moles of solution (no. of moles of solution = number of moles of solute + no. of moles of solvent).
- Press the “calculate” button and you will the answer.
The formula of mole fraction
The formula for calculation of mole fraction is given below
xsolute = no. of moles of solute / no. of moles of solution
(Mole percent) n / n % = xsolute x 100
If the number of moles of the solution is not given, then use the given formula.
Number of moles of solution = no. of moles of solute + no. of moles of solvent
Note that the sum of all the mole fractions of a solution is equal to 1. If the amount of solute and solvent are given in grams then first convert the number of grams to the moles, then apply the formula. The number of moles of an entity is calculated by
Number of moles = mass / molar mass
Or you may use our grams to moles calculator for a quick calculation.
The mole fraction of a gas (1) present in a mixture of gases is calculated as follows
x1 = P 1/P t
X1 is the mole fraction of gas 1, P1 is the partial pressure of gas 1, and Pt is the total pressure of the system (sum of partial pressure of all gases present in the system).
The concept of mole fraction is similar to molarity and molality where;
Molarity is the number of moles of a solute present in 1000 ml or 1 liter of a solution and molality is the number of moles of a solute in 1000 g or 1 kg of the solution.
Example # 1
Suppose you are given a solution of 10 moles of methanol in 20 moles of water. Calculate the mole fraction of the solute and solvent.
XCH3OH = no. of moles of CH3OH / no. of moles of CH3OH + no. of moles of H2O
XCH3OH = 10 / 10 + 20
XCH3OH = 10 / 30
XCH3OH = 0.3
The mole fraction of methanol is 0.3. Now, let’s calculate the mole fraction of water in the solution.
XH2O = no. of moles of H2O / no. of moles of CH3OH + no. of moles of H2O
xH2O = 20 / 10 + 20
xH2O = 20 / 30
xH2O = 0.6
The mole fraction of water in the solution is 0.6.
Example # 2
Calculate the mole fraction and mole percent of 56g CaO in 12 moles of solution.
First, convert the no. of grams of CaO to no. of moles.
No. of moles of CaO = mass / molar mass
No. of moles of CaO = 56g / 56 gmol-1
No. of moles of lime = 1 mole
X = no. of moles of lime / no. of moles of solution
X = 1 / 12
X = 0.07
n / n % = 0.07 x 100
n / n % = 7%
The mole fraction of CaO in 12 moles of the solution is 0.07 and the mole percent is 7%.
The mole fraction is a type of concentration. It is a unit less quantity. The physical method of calculating the mole fraction is time-consuming. So the mole fraction calculator is here to help you with these calculations. If the amount of solute is given in grams then first convert it to the no. of moles and then carry out the calculation.