Domanda del libro di testo
Methanol (CH3OH) can be made by the controlled oxidation of methane: CH4(g) + 12 O2(g) → CH3OH(g) (b) Will ΔG for the reaction increase, decrease, or stay unchanged with increasing temperature?
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Ch.19 - Chemical Thermodynamics
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970
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TOC.tableOfContents
- Ch.1 - Introduction: Matter, Energy, and Measurement146
- Ch.2 - Atoms, Molecules, and Ions200
- Ch.3 - Chemical Reactions and Reaction Stoichiometry176
- Ch.4 - Reactions in Aqueous Solution155
- Ch.5 - Thermochemistry126
- Ch.6 - Electronic Structure of Atoms131
- Ch.7 - Periodic Properties of the Elements126
- Ch.8 - Basic Concepts of Chemical Bonding123
- Ch.9 - Molecular Geometry and Bonding Theories143
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces91
- Ch.12 - Solids and Modern Materials122
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics174
- Ch.15 - Chemical Equilibrium101
- Ch.16 - Acid-Base Equilibria139
- Ch.17 - Additional Aspects of Aqueous Equilibria146
- Ch.18 - Chemistry of the Environment72
- Ch.19 - Chemical Thermodynamics129
- Ch.20 - Electrochemistry142
- Ch.21 - Nuclear Chemistry101
- Ch.22 - Chemistry of the Nonmetals68
- Ch.23 - Transition Metals and Coordination Chemistry66
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry10
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Non è quello che usi tu?Cambia libro di testo
Capitolo 19, Problema 73
Acetylene gas, C2H2(g), is used in welding. (b) How much heat is produced in burning 1 mol of C2H2 under standard conditions if both reactants and products are brought to 298 K?
Guida verificata passo dopo passo1
Identify the chemical reaction for the combustion of acetylene: \( \text{C}_2\text{H}_2(g) + \frac{5}{2} \text{O}_2(g) \rightarrow 2 \text{CO}_2(g) + \text{H}_2\text{O}(l) \).
Determine the standard enthalpy change of the reaction (\( \Delta H^\circ_{\text{rxn}} \)) using standard enthalpies of formation: \( \Delta H^\circ_{\text{rxn}} = \sum \Delta H^\circ_f(\text{products}) - \sum \Delta H^\circ_f(\text{reactants}) \).
Look up the standard enthalpies of formation for each substance involved in the reaction: \( \Delta H^\circ_f(\text{C}_2\text{H}_2(g)) \), \( \Delta H^\circ_f(\text{O}_2(g)) \), \( \Delta H^\circ_f(\text{CO}_2(g)) \), and \( \Delta H^\circ_f(\text{H}_2\text{O}(l)) \).
Substitute the values into the enthalpy change equation: \( \Delta H^\circ_{\text{rxn}} = [2 \times \Delta H^\circ_f(\text{CO}_2(g)) + \Delta H^\circ_f(\text{H}_2\text{O}(l))] - [\Delta H^\circ_f(\text{C}_2\text{H}_2(g)) + \frac{5}{2} \times \Delta H^\circ_f(\text{O}_2(g))] \).
Calculate the \( \Delta H^\circ_{\text{rxn}} \) to find the heat produced when 1 mol of \( \text{C}_2\text{H}_2 \) is burned under standard conditions.
Concetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Combustion Reaction
A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of acetylene (C2H2), the combustion reaction involves its reaction with oxygen to form carbon dioxide (CO2) and water (H2O). Understanding this reaction is crucial for calculating the heat produced, as it defines the stoichiometry and products involved.
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Percorso guidato
02:24
Combustion Apparatus
Enthalpy of Combustion
The enthalpy of combustion is the amount of heat released when one mole of a substance is completely burned in oxygen under standard conditions. This value is typically expressed in kilojoules per mole (kJ/mol) and is essential for determining the total heat produced in the combustion of acetylene. It can be found in thermodynamic tables or calculated using Hess's law.
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Percorso guidato
02:24Combustion Apparatus
Standard Conditions
Standard conditions refer to a set of specific conditions used as a reference point in thermodynamics, typically defined as 1 atmosphere of pressure and a temperature of 298 K (25°C). These conditions are important for ensuring consistency in thermodynamic measurements and calculations, such as determining the enthalpy of combustion, which is often reported under these standard conditions.
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Percorso guidato
01:10Standard Reduction Potentials
Pratica correlata
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The fuel in high-efficiency natural-gas vehicles consists primarily of methane (CH4). (a) How much heat is produced in burning 1 mol of CH4(g) under standard conditions if reactants and products are brought to 298 K and H2O(l) is formed?
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Domanda del libro di testo
(a) Using data in Appendix C, estimate the temperature at which the free-energy change for the transformation from I2(s) to I2(g) is zero. (b) Use a reference source, such as Web Elements (www.webelements.com), to find the experimental melting and boiling points of I2. (c) Which of the values in part (b) is closer to the value you obtained in part (a)?
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