Respuesta :
Answer:
Explanation:
To calculate the mole fraction of nitric acid (HNO₃) in concentrated nitric acid, we need to determine the number of moles of HNO₃ and the total number of moles in the solution.
Given that concentrated nitric acid is 70.4% HNO₃ by mass, we can assume that 100 grams of the solution contains 70.4 grams of HNO₃.
To find the moles of HNO₃, we need to divide the mass of HNO₃ by its molar mass. The molar mass of HNO₃ is calculated as follows:
H: 1.01 g/mol
N: 14.01 g/mol
O: 16.00 g/mol
So the molar mass of HNO₃ is:
1.01 + 14.01 + (3 * 16.00) = 63.01 g/mol
Now, we can calculate the moles of HNO₃:
moles of HNO₃ = mass of HNO₃ / molar mass of HNO₃
= 70.4 g / 63.01 g/mol
Next, we need to determine the total moles in the solution. Since the solution only contains HNO₃ and water (H₂O), the total moles are the sum of the moles of HNO₃ and moles of water.
The mole fraction of HNO₃ can then be calculated as:
mole fraction of HNO₃ = moles of HNO₃ / total moles
Let's calculate it:
mass_HNO3 = 70.4 # mass of HNO3 in grams
molar_mass_HNO3 = 63.01 # molar mass of HNO3 in g/mol
moles_HNO3 = mass_HNO3 / molar_mass_HNO3
total_moles = moles_HNO3 # Assuming no other components
mole_fraction_HNO3 = moles_HNO3 / total_moles
mole_fraction_HNO3
The mole fraction of nitric acid (HNO₃) in concentrated nitric acid is approximately 0.5.
