(a) Combustion analysis of 150.0 mg of 1,2,3,benzenetriol, a compound composed of carbon, hydrogen, and oxy-gen, gives 64.3 mg of H2O and 314.2 mg of CO2. What is the empirical formula of 1,2,3,benzenetriol?

Verified step by step guidance

1. Convert the mass of CO2 to moles of carbon: Use the molar mass of CO2 (44.01 g/mol) to find the moles of CO2, then use the ratio of carbon in CO2 to find moles of carbon.
2. Convert the mass of H2O to moles of hydrogen: Use the molar mass of H2O (18.02 g/mol) to find the moles of H2O, then use the ratio of hydrogen in H2O to find moles of hydrogen.
3. Determine the mass of carbon and hydrogen: Multiply the moles of carbon and hydrogen by their respective atomic masses (C: 12.01 g/mol, H: 1.008 g/mol) to find their masses.
4. Calculate the mass of oxygen in the compound: Subtract the combined mass of carbon and hydrogen from the total mass of the compound to find the mass of oxygen.
5. Convert the mass of oxygen to moles: Use the atomic mass of oxygen (16.00 g/mol) to find the moles of oxygen, then determine the simplest whole number ratio of moles of C, H, and O to find the empirical formula.

Key Concepts

Combustion Analysis

Combustion analysis is a technique used to determine the elemental composition of organic compounds. In this process, a sample is burned in excess oxygen, producing carbon dioxide and water. The masses of these products are measured, allowing for the calculation of the amounts of carbon and hydrogen in the original sample, which are essential for determining the empirical formula.

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present in that compound. It is derived from the amounts of each element obtained from combustion analysis. For example, if a compound contains 2 moles of carbon and 6 moles of hydrogen, its empirical formula would be CH3, reflecting the simplest ratio.

Mole Concept

The mole concept is a fundamental principle in chemistry that relates the mass of a substance to the number of particles it contains. One mole of any substance contains Avogadro's number (approximately 6.022 x 10^23) of entities, whether they are atoms, molecules, or ions. This concept is crucial for converting the mass of products from combustion analysis into moles, which are then used to find the empirical formula.