L3 Percent Composition

Open Ended

How many moles are in 50.7 grams of CH4?

Multiple Choice

What does 'percent composition' mean in the context of chemistry?

• The percent by mass of elements in a compound

• The percent by volume of a solution

• The percent of atoms in a molecule

• The percent of compounds in a mixture

Multiple Choice

In the compound NaCl, what is the percent composition of sodium (Na) if the mass of Na is 22.9 and the total mass of NaCl is 58.3?

• 39.3%

• 22.9%

• 58.3%

• 60.7%

Multiple Select

Which of the following are needed to calculate the percent composition of a compound?

• Mass of each element

• Total mass of compound

• Volume of compound

• Number of atoms of each element

Open Ended

Explain how you would calculate the percent composition of an element in a compound, using both simple and complex compounds as examples.

Multiple Choice

Which Excel sheet tab requires you to use a calculator to input the correct numbers and does not perform calculations for you?

• Sucrose

• Vanillin

• Sodium Bicarbonate

• Cacao

Multiple Choice

Which of the following tabs require you to work out calculations on paper and use the calculator to input the correct numbers?

• Sucrose only

• Vanillin, Sodium Bicarbonate, and Cacao

• All tabs

• None of the tabs

Multiple Choice

What is the percent composition by mass of calcium (Ca) in CaC2O4 (Calcium Oxalate)?

• 31.3%

• 25.0%

• 40.0%

• 18.7%

Open Ended

What is one thing you learned today about dimensional analysis or percent composition that you found interesting or useful?