Chemical Composition and Atomic Weights

This video tutorial, led by Jason from ASU tutoring centers, covers the concepts of formula weight and percent composition in chemistry. It begins with an introduction to formula weight, explaining it as the sum of atomic weights of each atom in a compound, using sucrose as an example. The tutorial details how to calculate atomic weights using the periodic table and demonstrates the calculation of sucrose's formula weight. It then explains how to determine the percent composition of elements within a compound. The session concludes with information on available tutoring resources.

What is the primary focus of the Chem 113 review session?

• Periodic table trends

• Formula weight and percent composition

• Chemical reactions

• Molecular geometry

How do you determine the formula weight of a compound?

• By summing the atomic weights of each atom in the compound

• By dividing the atomic weights of each atom in the compound

• By multiplying the atomic weights of all atoms

• By adding the atomic numbers of all atoms

What is the atomic weight of carbon as found on the periodic table?

• 13 AMU

• 12 AMU

• 11.99 AMU

• 12.01 AMU

Why are atomic weights not perfect integers?

• Because they are averages of isotopic masses

• Due to experimental errors

• Due to rounding off

• Because they are theoretical values

What is the formula weight of sucrose calculated in the session?

• 342.34 AMU

• 3423.4 AMU

• 34.234 AMU

• 34234 AMU

How many hydrogen atoms are present in sucrose?

• 12

• 22

• 11

• 6

What is the percent composition of carbon in sucrose?

• 42.1%

• 51.41%

• 6.49%

• 22.22%

Which element contributes the least to the mass of sucrose?

• Carbon

• Nitrogen

• Hydrogen

• Oxygen

How is percent composition calculated?

• By multiplying the atomic weights of each element

• By adding the atomic weights of each element

• By dividing the total mass of each element by the formula weight and multiplying by 100

• By subtracting the atomic weights from the formula weight

What is the percent composition of oxygen in sucrose?

• 42.1%

• 51.41%

• 6.49%

• 22.22%