Question 1:
What is the empirical formula of a compound that contains 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen by mass?
Explanation: The empirical formula represents the simplest whole-number ratio of atoms in a compound. To determine it, we convert the given percentages to moles and divide each by the smallest number of moles. In this case, the empirical formula is CH4.
Question 2:
What is the molecular formula of a compound with an empirical formula of CH2O and a molar mass of approximately 180 g/mol?
Explanation: The molecular formula represents the actual number of atoms of each element in a compound. To determine it, we need to know the molar mass. In this case, the molar mass of approximately 180 g/mol suggests that the molecular formula is C6H12O6 (glucose).
Question 3:
A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?
Explanation: To determine the empirical formula, we convert the given percentages to moles and divide each by the smallest number of moles. In this case, the empirical formula is C2H4O2 (acetic acid).
Question 4:
A compound has an empirical formula of C2H5 and a molar mass of approximately 58 g/mol. What is its molecular formula?
Explanation: To determine the molecular formula, we need to know the molar mass. In this case, the molar mass of approximately 58 g/mol suggests that the molecular formula is C4H10 (butane).
Question 5:
What is the empirical formula of a compound that contains 38.7% nitrogen and 61.3% oxygen by mass?
Explanation: To determine the empirical formula, we convert the given percentages to moles and divide each by the smallest number of moles. In this case, the empirical formula is N2O5 (dinitrogen pentoxide).