# Mole Fraction Calculation for Concentrated Nitric Acid

## What is the mole fraction of nitric acid in concentrated nitric acid?

The mole fraction of nitric acid is equal to its mass fraction, which is 0.704.

## Answer:

The mole fraction of nitric acid in concentrated nitric acid is 0.704.

Concentrated nitric acid is composed of 70.4% HNO3 by mass. To determine the mole fraction of nitric acid (HNO3) in concentrated nitric acid, we need to calculate the mole fraction using the given mass percent composition.

First, we convert the mass percent of HNO3 to a decimal form by dividing it by 100:

Mass percent of HNO3 = 70.4% = 0.704.

Next, we need to calculate the mass fraction of HNO3:

Mass fraction of HNO3 = mass of HNO3 / total mass of solution.

Since we are working with a pure substance (concentrated nitric acid), the total mass of the solution is equal to the mass of HNO3. Therefore, the mass fraction of HNO3 is also 0.704.

The mole fraction (X) is defined as the ratio of the moles of a component to the total moles of all components in the system. Since we have a pure substance, the total moles of all components are equal to the moles of HNO3. Therefore, the mole fraction of nitric acid is equal to its mass fraction, which is 0.704.