Determining Empirical and Molecular Formulas from Percent Composition

This video tutorial explains how to calculate empirical and molecular formulas from percent composition data. It begins by assuming a 100g sample to convert percent data into grams, then converts grams to moles using molar masses. The empirical formula is determined by comparing mole ratios, and the molecular formula is derived by comparing the molecular weight to the empirical formula weight.

What is the assumed total mass of the sample for simplifying calculations?

• 1 gram

• 10 grams

• 1000 grams

• 100 grams

How many grams of carbon are there in the sample?

• 40 grams

• 50 grams

• 30 grams

• 60 grams

What is the molar mass of hydrogen used in the calculations?

• 16 grams

• 14 grams

• 1.01 grams

• 12 grams

How many moles of oxygen are present in the sample?

• 6.64 moles

• 5 moles

• 2 moles

• 3.33 moles

What is the molar mass of carbon used in the calculations?

• 12 grams

• 1.01 grams

• 16 grams

• 14 grams

What is the empirical formula derived in the video?

• CH2O

• CHO

• C6H12O6

• C2H4O2

What is the ratio of carbon to hydrogen to oxygen in the empirical formula?

• 1:2:1

• 2:1:2

• 1:1:1

• 1:2:2

What is the molecular weight of the compound as given in the video?

• 160 grams/mole

• 200 grams/mole

• 150 grams/mole

• 180.16 grams/mole

How many empirical formula units are in the molecular formula?

• 2 units

• 4 units

• 8 units

• 6 units

What is the molecular formula of the compound?

• C12H24O12

• CH2O

• C6H12O6

• C3H6O3