Practice Problem: Empirical and Molecular Formulas

The video tutorial explains how to determine the molecular formula of nicotine using given mass percentages and molar mass. It starts with converting mass percentages to grams, then to moles, and uses these to find the empirical formula. Finally, it calculates the molecular formula by comparing the empirical formula mass to the given molar mass.

What is the first step in determining the molecular formula of nicotine?

• Find the empirical formula first.

• Assume a random mass for calculations.

• Convert mass percentages to grams.

• Calculate the molar mass directly.

How do you convert the mass of carbon in nicotine to moles?

• Multiply by 1 mole over 12.01 grams.

• Multiply by 1 mole over 16.00 grams.

• Multiply by 1 mole over 1.008 grams.

• Multiply by 1 mole over 14.01 grams.

Why is it important to convert mass percentages to moles in this calculation?

• Moles are the same as percentages.

• Moles are easier to calculate than grams.

• Moles allow for the determination of atomic ratios.

• Moles provide a direct measure of mass.

What is the empirical formula of nicotine based on the given calculations?

• C6H8N

• C4H6N

• C5H7N

• C10H14N2

What is the molar mass of nicotine as calculated in the tutorial?

• 81.13 grams per mole

• 162.3 grams per mole

• 100 grams per mole

• 200 grams per mole

How is the molecular formula of nicotine determined from the empirical formula?

• By adding one more nitrogen atom.

• By halving the empirical formula.

• By doubling the empirical formula.

• By tripling the empirical formula.

What is the final molecular formula of nicotine?

• C10H14N2

• C5H7N

• C6H8N

• C4H6N