The key difference between mass percent and percent composition is that the mass percent gives the ratio between the mass of a component in a mixture and the total mass of the mixture, whereas the percent composition gives the mass percentages of each chemical element in a mixture.
Although the terms mass percent and percent composition are used interchangeably, they are different terms. The mass percent refers to the percentage of a component in a mixture, while the percent composition refers to the percentage of a particular chemical element in a mixture.
CONTENTS
1. Overview and Key Difference
2. What is Mass Percent
3. What is Percent Composition
4. Side by Side Comparison – Mass Percent vs Percent Composition in Tabular Form
5. Summary
What is Mass Percent?
Mass percent is the percentage of the mass of a component in a mixture. The term describes the ratio between the mass of the desired component and the total mass of the mixture multiplied by 100 to get a percentage value. The formula for this determination is as follows:
Mass percent = (mass of the component/total mass of the mixture)*100
The denotation of the mass percent is as follows:
(w/w)%
Although the above formula gives a general idea about the mass percent, the application of the formula varies depending on the type of components and the mixture that we are dealing with. For example,
- For a chemical element in a compound, mass percent is calculated as follows:
Mass percent= (mass of the element per mole/mass of a mole of the compound)*100
- For a solute in a solution,
Mass percent =(grams of solute/grams of solute plus solvent)*100
What is Percent Composition?
Percent composition gives the mass percentages of each chemical element in a mixture. The term differs from mass percentage as a mass percentage gives the details about the composition of a chemical element, compound, and solute in a mixture, while the percent composition gives the mass percentages of all chemical elements.
Figure 01: Percent Composition of the Human Body
In other words, percent composition is the percentage by mass of each element in a compound. For example, the percent composition of a water molecule is 20% hydrogen and 80% oxygen.
What is the Difference Between Mass Percent and Percent Composition?
Although the terms mass percent and percent composition are used interchangeably, they are different terms. The key difference between mass percent and percent composition is that the mass percent gives the ratio between the mass of a component in a mixture and the total mass of the mixture, whereas the percent composition gives the mass percentages of each chemical element in a mixture. Furthermore, we can determine the mass percentage of water in salt by dividing the mass of water from the total mass of the sample, multiplied by 100. As an example for percent composition, we can say that percent composition of a water molecule is 20% hydrogen and 80% oxygen.
The below infographic summarizes the difference between mass percent and percent composition.
Summary – Mass Percent vs Percent Composition
Although the terms mass percent and percent composition are used interchangeably, they are different terms. In summary, the key difference between mass percent and percent composition is that the mass percent gives the ratio between the mass of a component in a mixture and the total mass of the mixture, whereas the percent composition gives the mass percentages of each chemical element in a mixture.
Reference:
1. Helmenstine, Anne Marie. “Mass Percentage Definition and Example.” ThoughtCo, Dec. 5, 2018, Available here.
2. Helmenstine, Anne Marie. “Percent Composition Definition.” ThoughtCo, Aug. 11, 2019, Available here.
Image Courtesy:
1. “201 Elements of the Human Body.02” By OpenStax College – This is a truncated version of File:201 Elements of the Human Body-01.jpg (CC BY 3.0) via Commons Wikimedia