Commercial aqueous nitric acid has a density of 1.42 g/mL and is 16 M. Calculate the percent HNO₃ by mass in the solution.

Key Concepts

Molarity (M)

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. In this case, a 16 M nitric acid solution means there are 16 moles of HNO3 in every liter of the solution. Understanding molarity is crucial for converting between moles and mass, which is necessary for calculating percent by mass.

Density

Density is the mass of a substance per unit volume, typically expressed in grams per milliliter (g/mL). The density of the nitric acid solution is given as 1.42 g/mL, which allows us to determine the mass of the solution when we know its volume. This relationship is essential for calculating the total mass of the solution needed to find the percent by mass of HNO3.

Percent by Mass

Percent by mass is a way to express the concentration of a component in a mixture, calculated as the mass of the solute divided by the total mass of the solution, multiplied by 100. To find the percent by mass of HNO3 in the solution, we need to determine the mass of HNO3 present and the total mass of the solution, which involves using both molarity and density.