When hydrocarbons are burned in a limited amount of air, both CO and CO2 form. When 0.450 g of a particular hydrocarbon was burned in air, 0.467 g of CO, 0.733 g of CO2, and 0.450 g of H2O were formed. (a) What is the empirical formula of the compound? (b) How many grams of O2 were used in the reaction? (c) How many grams would have been required for complete combustion?

Verified step by step guidance

Step 1: Determine the moles of CO and CO2 produced. Use the molar masses of CO (28.01 g/mol) and CO2 (44.01 g/mol) to convert the given masses to moles.

Step 2: Calculate the total moles of carbon atoms in the products. Since each mole of CO and CO2 contains one mole of carbon, add the moles of carbon from CO and CO2.

Step 3: Determine the moles of H2O produced. Use the molar mass of H2O (18.02 g/mol) to convert the given mass to moles. Each mole of H2O contains two moles of hydrogen atoms.

Step 4: Calculate the empirical formula. Use the moles of carbon and hydrogen obtained from the products to find the simplest whole number ratio of carbon to hydrogen in the hydrocarbon.

Step 5: Calculate the moles of oxygen used. Use the stoichiometry of the reaction to determine the moles of O2 consumed, considering the moles of CO, CO2, and H2O produced.

Key Concepts

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

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present in that compound. To determine the empirical formula, one must first convert the masses of the products formed during combustion into moles, then find the ratio of moles of each element. This concept is crucial for identifying the basic composition of the hydrocarbon in question.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on balanced chemical equations. Understanding stoichiometry is essential for determining how much O2 was used and how much would be needed for complete combustion.

Combustion Reaction

A combustion reaction is a chemical process in which a hydrocarbon reacts with oxygen to produce carbon dioxide and water, typically releasing energy. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide alongside carbon dioxide. Recognizing the differences between complete and incomplete combustion is vital for solving the problem regarding the amounts of O2 required.

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