The mass by mass percentage of a solution is the mass of the solute divided by the mass of the solution, multiplied by 100 to express it as a percentage.
Understanding Mass Percentage
Mass percentage, also known as weight percentage or mass fraction, is a way to express the concentration of a solute in a solution. It represents the mass of the solute present in 100 grams of the solution.
Formula for Mass Percentage
The formula for calculating mass percentage is:
Mass Percentage = (Mass of Solute / Mass of Solution) * 100
Where:
- Mass of Solute: The mass of the substance being dissolved (e.g., salt in saltwater).
- Mass of Solution: The total mass of the solution, which is the sum of the mass of the solute and the mass of the solvent (e.g., mass of salt + mass of water).
Calculating Mass Percentage: Example
Let's say you have a solution made by dissolving 20 grams of sugar in 80 grams of water.
- Identify the solute and solvent: Sugar is the solute, and water is the solvent.
- Determine the mass of the solute: Mass of sugar = 20 grams.
- Determine the mass of the solution: Mass of solution = Mass of sugar + Mass of water = 20 grams + 80 grams = 100 grams.
- Apply the formula:
Mass Percentage = (20 grams / 100 grams) * 100 = 20%
Therefore, the mass percentage of sugar in the solution is 20%.
Importance of Mass Percentage
Mass percentage is a useful way to express concentration because it is independent of temperature and pressure. It is widely used in various fields, including chemistry, food science, and pharmaceuticals, for preparing solutions and expressing the composition of mixtures.
