Mass Percentage: Overview, Questions, Preparation

The mass percent (mass %) of a component in a mixture is calculated using the following formula:

Mass percent (%) = (Mass of the component/Total mass of the mixture) × 100%

For example, if you have a solution that contains 10 grams of salt dissolved in 90 grams of water, you can calculate the mass percent of salt as follows:

Mass percent of salt =10g/(10 g (salt)+90 g (water)) × 100%

= (10 g/100 g) × 100%

= 10%

So, in this case, the mass percent of salt in the solution is 10%.

• Define the equation for mass percent of a compound. The formula for mass percent of a compound is mass percent = (mass of chemical÷total mass of compound) x 100. 
• Find the total mass of the compound. This may be the denominator within the mass percent calculation.
• Identify the mass of the given chemical. This mass is the numerator within the mass percent calculation.
• Substitute the values for variables into the mass percent equation.
• Determine the mass percent. Divide the mass of the chemical by the entire mass of the compound and multiply by 100. This gives you the mass percent of the chemical.