Percent Composition and Molar Mass

This video tutorial explains how to find the percent composition by mass of water in copper II nitrate hexahydrate. It begins with calculating the molar mass of the entire compound, including copper II nitrate and six water molecules. The tutorial then demonstrates using this molar mass to find the percent composition of water, resulting in 36.57%. The video concludes with a summary of the process.

What is the main focus of this video tutorial?

• Finding the percent composition by mass of copper in a compound

• Determining the molar mass of copper(II) nitrate

• Calculating the percent composition by mass of water in copper(II) nitrate hexahydrate

• Understanding the chemical properties of water

What is the first step in finding the percent composition by mass?

• Finding the density of the compound

• Calculating the molar mass of the entire compound

• Measuring the volume of the compound

• Identifying the number of water molecules

How many water molecules are associated with copper(II) nitrate in this compound?

• Seven

• Six

• Five

• Four

What is the molar mass of water used in the calculation?

• 22.02 grams per mole

• 20.00 grams per mole

• 18.02 grams per mole

• 16.00 grams per mole

Why do the units of grams per mole cancel out in the calculation?

• Because they are incorrect

• Because they appear in both the numerator and denominator

• Because they are not needed

• Because they are irrelevant to the calculation

What is the final percent composition of water in the compound?

• 30.57%

• 25.00%

• 36.57%

• 40.00%

What does the percent composition by mass tell us about the compound?

• The volume of the compound

• The density of the compound

• The proportion of the compound's mass that is water

• The total number of atoms in the compound