Percentage calculations involve determining the relative amount of a substance in a mixture compared to the whole. It can be expressed as a percentage by weight (% w/w), percentage by volume (% v/v), or percentage by mass (% m/m).
To calculate percentages, you typically need the following information:
1. Mass of the solute (the substance whose percentage you are calculating)
2. Mass or volume of the solution (the mixture containing the solute)
The chemical formula of the solute is not necessary for these calculations.
Here are the formulas to calculate different types of percentages:
Percentage by weight (% w/w):
% w/w = (Mass of solute / Mass of solution) * 100
Percentage by volume (% v/v):
% v/v = (Volume of solute / Volume of solution) * 100
Percentage by mass (% m/m):
% m/m = (Mass of solute / Mass of mixture) * 100
For example, if you have 10 grams of salt dissolved in 100 grams of water to make a saline solution, the percentage of salt in the solution by mass (% m/m) can be calculated as follows:
% m/m = (10 grams / 110 grams) * 100
% m/m ≈ 9.09%
In this calculation, the chemical formula of the solute (salt, NaCl) is not required to determine the percentage by mass.
