Domanda del libro di testo
Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. How does the energy of these fuels compare to that of octane (C8H18)?
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Ch.6 - Thermochemistry
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831
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TOC.tableOfContents
- Ch.1 - Matter, Measurement & Problem Solving136
- Ch.2 - Atoms & Elements112
- Ch.3 - Molecules, Compounds & Chemical Equations159
- Ch.4 - Chemical Quantities & Aqueous Reactions140
- Ch.5 - Gases118
- Ch.6 - Thermochemistry106
- Ch.7 - Quantum-Mechanical Model of the Atom62
- Ch.8 - Periodic Properties of the Elements103
- Ch.9 - Chemical Bonding I: The Lewis Model104
- Ch.10 - Chemical Bonding II: Molecular Shapes & Valence Bond Theory89
- Ch.11 - Liquids, Solids & Intermolecular Forces73
- Ch.12 - Solids and Modern Material59
- Ch.13 - Solutions110
- Ch.14 - Chemical Kinetics140
- Ch.15 - Chemical Equilibrium78
- Ch.16 - Acids and Bases155
- Ch.17 - Aqueous Ionic Equilibrium176
- Ch.18 - Free Energy and Thermodynamics108
- Ch.19 - Electrochemistry118
- Ch.20 - Radioactivity and Nuclear Chemistry82
- Ch.21 - Organic Chemistry150
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831Non è quello che usi tu?Cambia libro di testo
Capitolo 6, Problema 106
Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Use standard enthalpies of formation to calculate the amount of heat released per kilogram of methanol fuel and per kilogram of hydrogen fuel.
Guida verificata passo dopo passo1
Identify the chemical reactions for the combustion of methanol (CH₃OH) and hydrogen (H₂).
Write the balanced chemical equations for the combustion reactions: CH₃OH + 1.5O₂ → CO₂ + 2H₂O and 2H₂ + O₂ → 2H₂O.
Use standard enthalpies of formation (ΔH_f°) to calculate the enthalpy change (ΔH_rxn) for each reaction. ΔH_rxn = ΣΔH_f°(products) - ΣΔH_f°(reactants).
Determine the molar mass of methanol and hydrogen to convert the enthalpy change from per mole to per kilogram.
Calculate the heat released per kilogram by dividing the enthalpy change by the molar mass for each fuel.
Concetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Standard Enthalpy of Formation
The standard enthalpy of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states. It is a crucial value used in thermodynamics to calculate the heat released or absorbed during chemical reactions. For fuels like methanol and hydrogen, these values help determine their energy content and efficiency as alternatives to hydrocarbon fuels.
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Percorso guidato
02:34
Enthalpy of Formation
Heat of Combustion
The heat of combustion is the amount of energy released when a substance undergoes complete combustion with oxygen. This value is essential for evaluating the energy efficiency of fuels. By comparing the heat of combustion of methanol and hydrogen, one can assess which fuel releases more energy per kilogram, aiding in the selection of alternative fuels.
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Percorso guidato
02:24Combustion Apparatus
Stoichiometry
Stoichiometry involves the calculation of reactants and products in chemical reactions based on the balanced chemical equations. It is vital for determining the amount of heat released per kilogram of fuel, as it allows for the conversion of moles of fuel to mass and the calculation of energy changes during combustion. Understanding stoichiometry is essential for accurate thermodynamic calculations in fuel analysis.
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01:16Stoichiometry Concept
Pratica correlata
Domanda del libro di testo
Palmitic acid (C16H32O2) is a dietary fat found in beef and butter. The caloric content of palmitic acid is typical of fats in general. Write a balanced equation for the complete combustion of palmitic acid and calculate the standard enthalpy of combustion. What is the caloric content of palmitic acid in Cal/g? The standard enthalpy of formation of palmitic acid is -208 kJ/mol and that of sucrose is -2226.1 kJ/mol. [Use H2O(l) in the balanced chemical equations because the metabolism of these compounds produces liquid water.]
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Domanda del libro di testo
Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Which fuel contains the most energy in the least mass?
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Domanda del libro di testo
Palmitic acid (C16H32O2) is a dietary fat found in beef and butter. The caloric content of palmitic acid is typical of fats in general. Which dietary substance (sugar or fat) contains more Calories per gram? The standard enthalpy of formation of palmitic acid is -208 kJ/mol and that of sucrose is -2226.1 kJ/mol. [Use H2O(l) in the balanced chemical equations because the metabolism of these compounds produces liquid water.]
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