What is the formula for calculating mass percent?

The formula for calculating mass percent is based on the relationship between a specific part and the total mass of the mixture or sample. The correct formula states that you take the mass of the part you're interested in, divide it by the mass of the total, and then multiply that result by 100 to express it as a percentage. This approach allows you to quantify how much of the total mass is made up by the specific part, which is particularly useful in chemistry and materials science for understanding composition.

For example, if you have a mixture where the mass of the component is 20 grams and the total mass of the mixture is 200 grams, the mass percent would be calculated as (20 g / 200 g) x 100 = 10%. This formula is fundamental in various applications, including determining concentration, analyzing purity of substances, and in many other scenarios where mass fractions are important.

The other options do not correctly represent this relationship. Adding the mass of the part to the total or subtracting doesn't yield a meaningful percentage calculation, and using division in the wrong order will not provide the mass percent either. Thus, recognizing that the part's mass is the numerator and the total mass is the denominator is essential for correctly determining mass percent.