(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

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.

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.

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.

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.

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.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

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.

Recommended video:

Guided course

01:25

Mole Concept

Related Practice

Textbook Question

b) Given the mass spectrum of benzene, identify the molecular weight and give the molecular formula.

Textbook Question

(a) Combustion analysis of 50.0 mg of benzene, a commonly used solvent composed of carbon and hydrogen, gives 34.6 mg of H₂O and 169.2 mg of CO₂. What is the empirical formula of benzene?

Textbook Question

Assume that gasoline has the formula C8H18 and has a density of 0.703 g/mL. How many pounds of CO2 are produced from the complete combustion of 1.00 gal of gasoline?

Textbook Question

Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0.900 g of CO2 and 0.735 g of H2O are formed. What is the empirical formula of X?

Textbook Question

The molecular weight of ethylene glycol is 62.0689 when calculated using the atomic weights found in a standard periodic table, yet the molecular weight determined experimentally by high-resolution mass spectrometry is 62.0368. Explain the discrepancy.