Stoichiometry and Empirical Formulas Quiz

What is the primary focus of stoichiometry in chemistry?

• Studying the physical properties of elements

• Understanding chemical reactions and their quantitative aspects

• Analyzing the color changes in reactions

• Exploring the history of chemistry

Why is calcium carbonate a convenient sample for mass percent calculations?

• It is a rare compound

• Its molar mass is a round number, making calculations easier

• It has a molar mass of exactly 50 grams

• It reacts quickly with water

What is an intensive property in chemistry?

• A property that depends on the amount of substance

• A property that is unique to metals

• A property that changes with temperature

• A property that is independent of the sample size

How is an empirical formula different from a molecular formula?

• It is only used for ionic compounds

• It includes the molecular weight

• It represents the most reduced whole number ratio of atoms

• It shows the exact number of atoms in a molecule

What is the empirical formula for benzene (C6H6)?

• C6H6

• C2H2

• CH

• C3H3

When converting mass percent to an empirical formula, what is the first step?

• Convert atoms to grams

• Convert moles to atoms

• Convert grams to moles

• Convert grams to liters

If a compound has 80% carbon and 20% hydrogen by mass, what is the empirical formula?

• C4H1

• C1H3

• C2H6

• C3H9

What should you do if the mole ratio in an empirical formula calculation is not a whole number?

• Divide by the largest number

• Round up to the nearest whole number

• Ignore the decimal and use the integer part

• Multiply all ratios by a common factor to achieve whole numbers

How can you determine the molecular formula from an empirical formula?

• By calculating the melting point

• By using the molar mass of the compound

• By knowing the density of the compound

• By measuring the boiling point

If the empirical formula weight is 15 and the molecular weight is 30, what is the molecular formula?

• CH3

• C2H6

• C3H9

• C4H12