# Calculate the Density of a Solution

## How can we calculate the density of a solution based on the given data?

A student weighs an empty 20 ml volumetric flask and stopper and finds the mass to be 99.895 g. After adding an unknown substance to the flask, the same student adds water to the flask to dissolve the unknown substance to a total solution volume of 20.0 ml. The solution and flask are weighed again, and the resulting mass is 126.975 g. Calculate the density of this solution.

## Calculation of Density of the Solution:

First, we need to find the mass of the unknown substance:

Mass of unknown substance = Mass of flask, stopper, and solution - Mass of flask and stopper

Mass of unknown substance = 126.975 g - 99.895 g = 27.08 g

Next, we can calculate the density using the formula: density = mass / volume

The volume of the solution is 20.0 ml, which is equivalent to 20.0 cm^{3}.

Mass of solution = Mass of flask, stopper, and solution - Mass of flask and stopper

Mass of solution = 126.975 g - 99.895 g = 27.08 g

Now, we can calculate the density of the solution:

Density = Mass of solution / Volume of solution

Density = 27.08 g / 20.0 cm^{3}

**Density = 1.354 g/cm ^{3}**

In this calculation, we determined the mass of the unknown substance and the total mass of the solution to calculate the density. The density of a solution is defined as its mass per unit volume. By dividing the mass of the solution by its volume, we were able to find the density of the solution to be 1.354 g/cm^{3}.

Understanding how to calculate density is important in various scientific fields, as it allows us to characterize the properties of substances. Density is a physical property that helps in identifying and classifying materials based on their mass per unit volume.

By following the steps outlined above, we were able to determine the density of the solution accurately. This calculation showcases the application of basic principles of chemistry, such as mass and volume calculations, in determining the density of solutions.