Percent Composition in Compounds

The video tutorial explains how to calculate the percent composition by mass of each element in ammonium carbonate (NH4)2CO3. It begins with nitrogen, detailing the use of molar mass and the number of atoms to find its percent composition. The same method is applied to hydrogen and carbon, with specific attention to the number of atoms involved. Finally, the video covers the calculation for oxygen, ensuring the total percent composition is close to 100%. The tutorial concludes with a summary of the process.

What is the first step in finding the percent composition by mass of an element in a compound?

• Divide the molar mass of the element by the total molar mass of the compound.

• Multiply the atomic mass of the element by the number of atoms of that element.

• Subtract the atomic mass of the element from the total molar mass of the compound.

• Add the atomic masses of all elements in the compound.

How many nitrogen atoms are present in ammonium carbonate?

• One

• Four

• Two

• Three

What is the percent composition by mass of nitrogen in ammonium carbonate?

• 99.94%

• 29.15%

• 8.41%

• 12.50%

How many hydrogen atoms are present in ammonium carbonate?

• Six

• Ten

• Four

• Eight

What is the percent composition by mass of hydrogen in ammonium carbonate?

• 99.94%

• 29.15%

• 12.50%

• 8.41%

What is the percent composition by mass of carbon in ammonium carbonate?

• 99.94%

• 29.15%

• 8.41%

• 12.50%

How many oxygen atoms are present in ammonium carbonate?

• Four

• One

• Two

• Three

What is the percent composition by mass of oxygen in ammonium carbonate?

• 29.15%

• 99.94%

• 8.41%

• 12.50%

What should the sum of all percent compositions in a compound ideally be?

• 100%

• 75%

• 50%

• 150%

Who is the presenter of the video on percent composition?

• Dr. C

• Dr. D

• Dr. B

• Dr. A