Question

If we take 44g of CO2 and 14g of N2 what will be the mole fraction of CO2 in the mixture
A . 1/5
B . 1/3
C . 2/3
D . 1/4

Answer 1

Hint: In this question we have to use the concept of mole fraction. A unit of concentration is a mole fraction. It shows the percentage of moles of a specific component there are in a solution. It is a fraction with no units.

Complete answer:The number of moles of the same component in a solution divided by the total moles of all the solution's constituents is known as the mole fraction of that component. The amount fraction is another name for the mole fraction. The mixture can be made by weighing off the necessary masses of the constituent parts if the mole fraction is known.
In a solution, the mole fraction of the ith component is expressed as follows:
\[{{X}_{i}}=\dfrac{{{n}_{i}}}{{{n}_{total}}}\]
All of the mole fractions of the components in a solution added together equal one.
The mole fraction is independent of temperature. In a combination of ideal gases, it can be written as the partial pressure to total pressure ratio.
Mole fraction of CO2= ${{X}_{C{{O}_{2}}}}=\dfrac{{{n}_{C{{O}_{2}}}}}{{{n}_{C{{O}_{2}}}}+{{n}_{{{N}_{2}}}}}$
Mass of CO2=44 and that of N2=14
${{X}_{C{{O}_{2}}}}=\dfrac{\dfrac{44}{44}}{\dfrac{44}{44}+\dfrac{14}{28}}=\dfrac{2}{3}$

The correct answer is C.

Note: Mole fraction, molar concentration, and mass fraction are all easily confused. Molar concentration is a ratio of moles to volume, the mass fraction is a ratio of mass and moles, and the mole fraction is a unitless fraction.
The ratio of a substance's mass to the overall mass of the mixture is known as the mass fraction of that substance in the mixture.
Molar concentration is a proportion of moles to volume, whereas mole fraction is a ratio of moles to moles. One technique to indicate the composition of a mixture using a dimensionless quantity is the mole fraction; additional options are the mass fraction (percentage by weight, wt%) and the volume fraction (percentage by volume, vol%).