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%

Fill in the Blanks

Percent composition is calculated as (mass of an element /

) x 100.

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

Fill in the Blanks

The cells in the Excel sheet will highlight

if correct and red if wrong.

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?