Textbook Question
Combustion analysis of a hydrocarbon produces 33.01 g CO2 and 13.51 g H2O. Calculate the empirical formula of the hydrocarbon.
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Ch.3 - Molecules, Compounds & Chemical Equations
Chapter 3, Problem 100
Tartaric acid is the white, powdery substance that coats tart candies such as Sour Patch Kids. Combustion analysis of a 12.01-g sample of tartaric acid—which contains only carbon, hydrogen, and oxygen—produces 14.08 g CO2 and 4.32 g H2O. Determine the empirical formula of tartaric acid.
Verified step by step guidance1
Calculate the moles of carbon in the CO2 produced using the molar mass of CO2.
Calculate the moles of hydrogen in the H2O produced using the molar mass of H2O.
Determine the mass of carbon and hydrogen in the original sample using their respective moles and atomic masses.
Subtract the mass of carbon and hydrogen from the total mass of the sample to find the mass of oxygen.
Convert the masses of carbon, hydrogen, and oxygen to moles, then find the simplest whole number ratio to determine the empirical formula.
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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, and the products, typically carbon dioxide (CO2) and water (H2O), are measured. The masses of these products allow for the calculation of the amounts of carbon, hydrogen, and oxygen in the original sample, which is essential for determining the empirical formula.
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Combustion of Non-Hydrocarbons
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 moles of each element calculated from the mass of the products obtained during combustion analysis. This formula does not provide information about the actual number of atoms in a molecule but is crucial for understanding the basic composition of the substance.
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02:26Empirical vs Molecular Formula
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 vital for converting the mass of carbon, hydrogen, and oxygen obtained from combustion into moles, which are then used to determine the empirical formula.
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Related Practice
Textbook Question
Combustion analysis of naphthalene, a hydrocarbon used in mothballs, produces 8.80 g CO2 and 1.44 g H2O. Calculate the empirical formula of naphthalene.
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Textbook Question
The foul odor of rancid butter is due largely to butyric acid, a compound containing carbon, hydrogen, and oxygen. Combustion analysis of a 4.30-g sample of butyric acid produces 8.59 g CO2 and 3.52 g H2O. Determine the empirical formula of butyric acid.
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Textbook Question
Sulfuric acid is a component of acid rain formed when gaseous sulfur dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous sulfuric acid. Write the balanced chemical equation this reaction. (Note: this is a simplified representation of this reaction.)
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Textbook Question
Nitric acid is a component of acid rain that forms when gaseous nitrogen dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous nitric acid. Write the balanced chemical equation for this reaction. (Note: this is a simplified representation of this reaction.)
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Open Question
In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. What is the balanced chemical equation for this reaction?