Empirical and Molecular Formulas

The video tutorial covers the calculation of empirical and molecular formulas, using percent abundance and molar mass. It demonstrates how to determine the mass and number of atoms in a gold bar using density and volume. Finally, it explains how to find the empirical formula of gold oxide, including the calculation of moles and the determination of charges in compounds.

What is the first step in determining the empirical formula from percent abundance?

• Convert moles to liters

• Convert moles to grams

• Convert grams to moles

• Convert grams to liters

How do you find the molecular formula from the empirical formula?

• Multiply the empirical formula by the molar mass of the compound

• Divide the empirical formula by the molar mass of the compound

• Multiply the empirical formula by the ratio of the compound's molar mass to the empirical formula's molar mass

• Divide the empirical formula by the ratio of the compound's molar mass to the empirical formula's molar mass

What is the formula to calculate the volume of a gold bar?

• Length + Width + Height

• Length x Width x Height

• Length x Width + Height

• Length + Width x Height

How do you convert the mass of gold to the number of atoms?

• Convert to moles and then divide by Avogadro's number

• Multiply by Avogadro's number

• Divide by Avogadro's number

• Convert to moles and then multiply by Avogadro's number

What is the first step in determining the number of moles of oxygen in a gold oxide compound?

• Add the mass of gold and oxygen

• Subtract the mass of gold from the total mass of the compound

• Divide the mass of gold by the mass of oxygen

• Multiply the mass of gold by the mass of oxygen

How do you determine the empirical formula of a compound?

• By finding the ratio of the number of moles

• By finding the ratio of the number of atoms

• By finding the ratio of the number of liters

• By finding the ratio of the number of grams

What is the empirical formula for a compound with a 1:1.5 ratio of elements?

• Multiply both by 2 to get a whole number ratio

• Multiply both by 1.5 to get a whole number ratio

• Multiply both by 3 to get a whole number ratio

• Multiply both by 0.5 to get a whole number ratio

What is the charge of gold in the compound Au2O3?

• +1

• +2

• +3

• +4

How do you determine the charge of an element in a compound?

• By measuring the mass of the compound

• By using the empirical formula and known charges of other elements

• By calculating the density of the compound

• By looking at the periodic table

What is the name of the compound with the formula Au2O3?

• Gold(IV) oxide

• Gold(III) oxide

• Gold(II) oxide

• Gold(I) oxide