Empirical and Molecular Formulas Quiz

What is the main difference between empirical and molecular formulas?

• Empirical formulas are always in the simplest ratio.

• Molecular formulas show the percentage composition of elements.

• Molecular formulas are always in the simplest ratio.

• Empirical formulas show the actual number of atoms in a compound.

How do you convert a percentage composition to grams when calculating an empirical formula?

• Convert the percentage to a fraction and multiply by 1000.

• Divide the percentage by the atomic mass.

• Assume a 100 gram sample and convert the percentage directly to grams.

• Multiply the percentage by the molar mass.

What is the next step after converting grams to moles in empirical formula calculation?

• Add the moles together.

• Divide all mole values by the largest mole value.

• Divide all mole values by the smallest mole value.

• Multiply the moles by the atomic number.

When converting an empirical formula to a molecular formula, what information is essential?

• The density of the compound.

• The molar mass of the molecular formula.

• The boiling point of the compound.

• The color of the compound.

In the example of converting SiO2 to its molecular formula, what was the whole number used to multiply the empirical formula?

• 3

• 5

• 4

• 6

What is the first step in determining the empirical formula for nicotine?

• Determine the boiling point of nicotine.

• Calculate the density of nicotine.

• Write the percentage composition as grams.

• Convert the molar mass to grams.

After converting grams to moles for nicotine, what is the next step?

• Multiply the moles by the atomic number.

• Convert moles back to grams.

• Divide each mole value by the smallest mole value.

• Add the moles together.

What is the empirical formula for nicotine based on the given example?

• C5H7N

• C6H12O6

• C10H14N2

• C3H7N

How is the molecular formula for nicotine determined from its empirical formula?

• By multiplying the empirical formula by a whole number derived from dividing the molecular mass by the empirical mass.

• By calculating the density of nicotine.

• By dividing the empirical formula mass by the molecular formula mass.

• By adding the atomic masses of all elements.

What is the molecular formula for nicotine as calculated in the example?

• C5H7N

• C3H7N

• C10H14N2

• C6H12O6