Skip to main content
Ch.3 - Chemical Reactions and Reaction Stoichiometry
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoBrown 14th EditionCh.3 - Chemical Reactions and Reaction StoichiometryProblema 95
Capitolo 3, Problema 95

Vanillin, the dominant flavoring in vanilla, contains C, H, and O. When 1.05 g of this substance is completely combusted, 2.43 g of CO2 and 0.50 g of H2O are produced. What is the empirical formula of vanillin?

Guida verificata passo dopo passo
1
Determine the moles of carbon in CO2 by using the molar mass of CO2 (44.01 g/mol) and the fact that each mole of CO2 contains one mole of carbon.
Calculate the moles of hydrogen in H2O by using the molar mass of H2O (18.02 g/mol) and the fact that each mole of H2O contains two moles of hydrogen.
Find the mass of carbon and hydrogen in the original sample by multiplying the moles of each element by their respective atomic masses (C: 12.01 g/mol, H: 1.008 g/mol).
Subtract the mass of carbon and hydrogen from the total mass of the sample to find the mass of oxygen.
Convert the mass of oxygen to moles using the atomic mass of oxygen (16.00 g/mol), then determine the simplest whole number ratio of moles of C, H, and O to find the empirical formula.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
4m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Combustion Analysis

Combustion analysis is a technique used to determine the elemental composition of organic compounds. During this process, a sample is burned in excess oxygen, producing carbon dioxide (CO2) and water (H2O). The masses of these products are measured to infer the amounts of carbon and hydrogen in the original compound, which is essential for deriving its empirical formula.
Video consigliato:
Percorso guidato
01:29
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 products obtained during combustion. This formula provides insight into the basic composition of the substance, although it may not reflect the actual molecular structure.
Video consigliato:
Percorso guidato
02:26
Empirical vs Molecular Formula

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It involves using balanced chemical equations to calculate the amounts of substances consumed and produced. In the context of combustion analysis, stoichiometry helps convert the masses of CO2 and H2O into moles of carbon and hydrogen, which are crucial for determining the empirical formula.
Video consigliato:
Percorso guidato
01:16
Stoichiometry Concept
Pratica correlata
Domanda del libro di testo
Cinnamaldehyde is a compound that is responsible for the characteristic aroma of cinnamon. It contains 81.79% C, 6.10% H, and the remaining is oxygen. Its molar mass is 132 g/mol. Determine its molecular formula.
1607
views
Domanda del libro di testo
The fluoride ion reacts with water to produce HF. (a) Write out the chemical equation for this reaction.
1317
views
Domanda del libro di testo

An organic compound was found to contain only C, H, and Cl. When a 1.50-g sample of the compound was completely combusted in air, 3.52 g of CO2 was formed. In a separate experiment, the chlorine in a 1.00-g sample of the compound was converted to 1.27 g of AgCl. Determine the empirical formula of the compound.

2587
views
2
rank
Domanda del libro di testo

An element X forms an iodide (XI3) and a chloride (XCl3). The iodide is quantitatively converted to the chloride when it is heated in a stream of chlorine: 2 XI3 + 3 Cl2 → 2 XCl3 + 3 I2 If 0.5000 g of XI3 is treated with chlorine, 0.2360 g of XCl3 is obtained. (a) Calculate the atomic weight of the element X. (b) Identify the element X.

992
views
Domanda del libro di testo

(b) Hemoglobin, the oxygen-carrying protein in red blood cells, has four iron atoms per molecule and contains 0.340% iron by mass. Calculate the molar mass of hemoglobin.

1609
views
Domanda del libro di testo
A compound, Na2Cr2Ox, where x is unknown, is analyzed and found to contain 39.70% Cr. What is the value of x?
393
views