Question

what is mass percentage composition of an element​

Answer 1

Answer:

For a solution, mass percent equals the mass of an element in one mole of the compound divided by the molar mass of the compound, multiplied by 100%.

Answer 2

by

Anne Marie Helmenstine, Ph.D.

Updated August 08, 2019

This is a worked example problem showing how to calculate mass percent composition. Percent composition indicates the relative amounts of each element in a compound. For each element, the mass percent formula is:

% mass = (mass of element in 1 mole of the compound) / (molar mass of the compound) x 100%

or

mass percent = (mass of solute / mass of solution) x 100%

The units of mass are typically grams. Mass percent is also known as percent by weight or w/w%. The molar mass is the sum of the masses of all the atoms in one mole of the compound. The sum all the mass percentages should add up to 100%. Watch for rounding errors in the last significant figure to make sure all the percentages add up.