Calculating Percent Composition in Chemical Compounds

The video tutorial explains how to calculate percent composition by mass, using examples of water (H2O), iron(III) chloride (FeCl3), and a carbon compound (C6H10O4). It covers the steps to determine the molar mass of compounds and individual elements, and how to use these values to find the percent composition by mass. The tutorial emphasizes understanding the formula and applying it to different chemical compounds.

What is the formula used to calculate percent composition by mass?

• Molar mass of compound / Molar mass of element x 100%

• Molar mass of compound - Molar mass of element x 100%

• Molar mass of element + Molar mass of compound x 100%

• Molar mass of element / Molar mass of compound x 100%

In the calculation of percent composition of hydrogen in water, what is the molar mass of water (H2O)?

• 16.00 g/mol

• 18.02 g/mol

• 14.02 g/mol

• 20.02 g/mol

How many hydrogen atoms are present in a molecule of water (H2O)?

• One

• Two

• Three

• Four

What is the percent composition by mass of hydrogen in water (H2O)?

• 11.2%

• 8.9%

• 15.5%

• 10.0%

In FeCl3, how many chlorine atoms are present?

• Four

• One

• Two

• Three

What is the percent composition by mass of iron in FeCl3?

• 34.43%

• 25.67%

• 28.56%

• 40.00%

What is the molar mass of the entire compound C6H10O4?

• 140.2 g/mol

• 120.2 g/mol

• 146.2 g/mol

• 160.2 g/mol

How many carbon atoms are present in the compound C6H10O4?

• Six

• Eight

• Ten

• Four

What is the percent composition by mass of carbon in C6H10O4?

• 50.00%

• 55.29%

• 45.00%

• 49.29%

What is another term for percent composition by mass?

• Molar percentage

• Mass percentage

• Elemental percentage

• Atomic percentage