Ethanol Composition and Properties

This video tutorial explains how to calculate the percent composition by mass of each element in the ethanol molecule, C2H5OH. It begins by discussing the different ways ethanol can be represented and highlights the importance of the alcohol functional group. The tutorial then guides viewers through calculating the molar mass of ethanol and determining the percent composition of carbon, hydrogen, and oxygen in the compound. Each step involves using the periodic table to find atomic masses, multiplying by the number of atoms, and dividing by the molar mass of the compound to find the percentage. The video concludes by ensuring the calculated percentages sum up to approximately 100%.

What is the chemical formula for ethanol as mentioned in the video?

• C2H5OH

• C2H6OH

• C2H4O

• C3H7OH

What is the first step in finding the percent composition of ethanol?

• Determine the number of atoms in the compound

• Identify the functional group

• Find the molar mass of the entire compound

• Calculate the molar mass of each element

What is the molar mass of ethanol as calculated in the video?

• 48.02 g/mol

• 44.01 g/mol

• 46.08 g/mol

• 50.05 g/mol

How many carbon atoms are present in ethanol?

• 4

• 3

• 2

• 1

What is the percent composition of carbon in ethanol?

• 54.00%

• 50.00%

• 48.00%

• 52.13%

How many hydrogen atoms are present in ethanol?

• 4

• 5

• 6

• 7

What is the percent composition of hydrogen in ethanol?

• 12.5%

• 15.0%

• 13.8%

• 14.2%

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

• 18.00 g/mol

• 17.00 g/mol

• 16.00 g/mol

• 15.99 g/mol

What is the percent composition of oxygen in ethanol?

• 35.00%

• 34.72%

• 36.00%

• 33.00%

What should the sum of the percent compositions of all elements in ethanol be close to?

• 90%

• 100%

• 105%

• 95%