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Ch.5 - Thermochemistry
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Brown 14th EditionCh.5 - Thermochemistry문제 39b
5장, 문제 39b

The complete combustion of methane, CH4(g), to form H2O(l) and CO2(g) at constant pressure releases 890 kJ of heat per mole of CH4. (b) Draw an enthalpy diagram for the reaction.

검증된 단계별 안내
1
Draw a horizontal line to represent the enthalpy level of the reactants, which is methane (CH_4) and oxygen (O_2).
Draw another horizontal line below the reactants' line to represent the enthalpy level of the products, which are carbon dioxide (CO_2) and water (H_2O).
Label the vertical distance between the reactants and products as the change in enthalpy (ΔH), which is -890 kJ/mol, indicating an exothermic reaction.
Add an arrow pointing downward from the reactants' line to the products' line to show the release of energy.
Label the reactants' line with 'CH_4 + 2O_2' and the products' line with 'CO_2 + 2H_2O'.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Enthalpy (H)

Enthalpy is a thermodynamic property that represents the total heat content of a system at constant pressure. It is defined as the sum of the internal energy and the product of pressure and volume (H = U + PV). In chemical reactions, changes in enthalpy (ΔH) indicate whether a reaction is exothermic (releases heat) or endothermic (absorbs heat), which is crucial for understanding energy changes during combustion.
추천 영상:
가이드 코스
02:34
Enthalpy of Formation

Combustion Reaction

A combustion reaction is a chemical process in which a substance (typically a hydrocarbon) reacts with oxygen to produce carbon dioxide and water, releasing energy in the form of heat. In the case of methane (CH4), its complete combustion yields CO2 and H2O, and is characterized by a significant release of energy, as indicated by the 890 kJ of heat released per mole of CH4 in the question.
추천 영상:
가이드 코스
02:24
Combustion Apparatus

Enthalpy Diagram

An enthalpy diagram visually represents the changes in enthalpy during a chemical reaction. It typically shows the enthalpy of the reactants and products, along with the enthalpy change (ΔH) for the reaction. For the combustion of methane, the diagram would illustrate the higher enthalpy of the reactants compared to the lower enthalpy of the products, indicating the exothermic nature of the reaction and the energy released.
추천 영상:
가이드 코스
02:34
Enthalpy of Formation
관련 실천
교과서 질문

The decomposition of sodium bicarbonate (baking soda), NaHCO3(s), into Na2CO3(s), H2O(l), and CO2(g) at constant pressure requires the addition of 85 kJ of heat per two moles of NaHCO3. (a) Write a balanced thermochemical equation for the reaction.

교과서 질문

The complete combustion of methane, CH4(g), to form H2O(l) and CO2(g) at constant pressure releases 890 kJ of heat per mole of CH4. (a) Write a balanced thermochemical equation for this reaction.

교과서 질문

Atomic hydrogen (H) is used in welding (AHW). The atoms recombine to hydrogen molecules with a large release of heat according to the following reaction: 2 H(g) → H2(g) (b) Which has the higher enthalpy under these conditions, 2 H(g) or H2(g)?

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교과서 질문

A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in Figure 5.4. When 0.49 kJ of heat is added to the gas, it expands and does 214 J of work on the surroundings. What are the values of H and E for this process?

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교과서 질문

Atomic hydrogen (H) is used in welding (AHW). The atoms recombine to hydrogen molecules with a large release of heat according to the following reaction: 2 H(g) → H2(g)  (a) Using the thermodynamic data in Appendix C, calculate the enthalpy change for this reaction per mole of H2.