What is an example of mass by mass?

A practical example of mass by mass, often expressed as a percentage (% m/m), is found in the calculation of the amount of solute in a solution. Specifically, calculating the grams of a compound in a solution when given its mass percentage is an example.

Understanding Mass by Mass

Mass by mass, or weight by weight, represents the concentration of a solution by expressing the mass of solute in grams present in 100 grams of the solution. This is a common way to measure the concentration of solid solutes in liquid solutions or even in other solid mixtures. The formula to calculate mass by mass percentage is as follows:

Mass Percentage (%) = (Mass of Solute / Mass of Solution) * 100

Example Using Bleach Solution

Let's consider the provided example using a billboard bleach solution containing sodium hypochlorite (NaOCl):

• Problem: Calculate the grams of NaOCl in 285 grams of a bleach solution that is 6.15% by mass.
• Understanding: The 6.15% mass by mass means that there are 6.15 grams of NaOCl for every 100 grams of the bleach solution.
• Calculation:
  1. We rearrange the mass percentage formula to find the mass of the solute:
     • Mass of Solute = (Mass Percentage * Mass of Solution) / 100
  2. Substitute the values:
     • Mass of NaOCl = (6.15 * 285) / 100
  3. The result is:
     • Mass of NaOCl = 17.52 grams

This result tells us that there are 17.52 grams of NaOCl in 285 grams of the 6.15% billboard bleach solution.

Practical Application

Here's how this principle can be applied in other scenarios:

• Food industry: Calculating the amount of sugar in a syrup or salt in a brine solution.
• Pharmaceuticals: Determining the correct amount of active ingredient in a medication.
• Chemical industry: Formulating specific mixtures or solutions for laboratory or industrial processes.
• Everyday products: Understanding the composition of cleaning products or beauty supplies.

In summary, the example of calculating the mass of NaOCl in a bleach solution using its mass percentage illustrates a practical application of mass by mass measurements. This method is crucial for accurately determining the amount of solute present in a given quantity of solution across numerous fields.