# 2.10: Percent Composition

## Mass percent composition

The percentage composition is very simple. Percent composition tells you the percentage of each element present in a compound by mass. A chemical compound is a combination of two or more elements. If you are studying a chemical compound, you may want to find the percent composition of a certain element in that chemical compound. The percent composition equation is (element mass / molecular mass) x 100. If you want to know the percent composition of the elements in a compound, follow these steps: Solving steps: Read : mass percent of chlorine in hydrochloric acid

• Find the molar masses of all the elements in the compound, in grams per mole.
• Find the molecular mass of the whole compound.
• Divide the molar mass of the component by the total molecular mass.
• You should now have a number between 0 and 1. Multiply it by 100 to get the percent component!
• Read more: Which episode Luffy uses gears 2 Solving tips:

• Compounds will always add up to 100%, so in a binary compound you can find the % of the first element, then do 100% – (% of the first element) to get the (% of the first element) second death)
• If using a calculator, you can store the overall molar mass in a variable such as “A”. This will speed up calculations and reduce typographical errors.
• These steps are shown in the figure below. Read more: what is the greatest common factor of 10 and 15As another example, if you want to know the percent composition of hydrochloric acid (HCl), first find the molar mass of Hydrogen. H = 1.00794 grams. Now find the molecular mass of HCl: 1.00794g + 35.4527g = 36.46064g. Follow steps 3 and 4: (1.00794g / 36.46064g) x 100 = 2.76% Now just subtract to find the percent composition by mass of Chlorine in the compound: 100% -2, 76% = 97.24% Hence HCl is 2.76% Hydrogen and 97.24% Chlorine by mass. Further reading: Is 38 a prime number?