Tier Lebih Tinggi: gabungkan persamaan setengah sel bahan bakar hidrogen
Diperkenalkan| English | Makna |
|---|---|
| fuel-cell anode/ˈfjuːəl sel ˈænəʊd/ | anoda sel bahan bakar |
| fuel-cell cathode/ˈfjuːəl sel ˈkæθəʊd/ | katoda sel bahan bakar |
What would explain this observation?
- Higher Tier: A hydrogen fuel cell separates oxidation and reduction at two electrodes. The same number of electrons must be released at one electrode and accepted at the other.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- For the explicitly acidic-electrolyte model, hydrogen oxidation is 2H₂ → 4H⁺ + 4e⁻. Oxygen reduction is O₂ + 4H⁺ + 4e⁻ → 2H₂O. Adding the half equations cancels four hydrogen ions and four electrons, leaving 2H₂ + O₂ → 2H₂O. Oxidation means electron loss and reduction electron gain. These half equations are the embedded Higher-only part of the source section.
- fuel-cell anode 燃料电池阳极: The electrode where hydrogen oxidation releases electrons in the stated generating cell; fuel-cell cathode 燃料电池阴极: The electrode where oxygen reduction accepts electrons in the stated generating cell.
Persamaan separuh hidrogen asam mana yang menunjukkan oksidasi?
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Oksidasi melepaskan elektron, sehingga persamaan setengah reaksi hidrogen adalah H2 -> 2H+ + 2e-, setara untuk atom (2:2) dan muatan (0 di kedua sisi). Elektron di sebelah kiri akan menggambarkan reduksi, dan oksigen saja tidak dapat membentuk air tanpa spesies hidrogen.
Pasangkan setiap istilah teknis dengan maknanya yang tepat.
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Gunakan definisi untuk membedakan besaran dan proses yang terkait.
Choose evidence that can test it
- Check atoms and charges separately. The hydrogen half equation has four hydrogen atoms on each side and zero net charge because +4 from H⁺ balances −4 from electrons. The oxygen half equation has two oxygen atoms and four hydrogen atoms on each side, again zero net charge. In this generating cell electrons leave the hydrogen anode through the external circuit and reach the oxygen cathode. The anode is negative and the cathode positive while the cell supplies electricity.
- Begin with one consistent electrolyte model. Balance hydrogen with H⁺, oxygen with water and charge with electrons, then scale to equal electron numbers and cancel. Do not mix an acidic half equation with an alkaline one containing OH⁻. The electrode names identify oxidation at the anode and reduction at the cathode; signs must be interpreted for a generating fuel cell, rather than copied from an externally powered electrolytic cell.
Dua kebiasaan manakah yang membuat penyelidikan atau model dalam kasus ini lebih dapat dipertanggungjawabkan?
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Menyatakan kondisi dan asumsi memungkinkan orang lain mengulangi pekerjaan persis seperti itu, dan mencatat bukti pendukung memungkinkan mereka memeriksa kesimpulan. Menyembunyikan hasil yang bertentangan menghilangkan bukti yang dapat menentang kesimpulan yang salah, dan satu pengukuran tidak pernah dapat menetapkan klaim yang lebih luas.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: starting from H₂ → 2H⁺ + 2e⁻, multiply by two to match the four electrons consumed by O₂ + 4H⁺ + 4e⁻ → 2H₂O. Two represented H₂ molecules supply four electrons and one O₂ molecule accepts four. If three O₂ molecules react in the same scaled model, twelve electrons pass through the external circuit and six H₂O molecules form. Electrons cancel from the overall equation.
Each represented H₂ molecule releases two electrons in the stated half equation. How many are released by eight H₂ molecules? Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Setiap molekul H₂ yang diwakili melepaskan dua elektron dalam persamaan separuh yang disebutkan. Berapa banyak yang dilepaskan oleh delapan molekul H₂?
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Hasilnya adalah 16 elektron. Diketahui: setiap molekul H2 melepaskan 2 elektron dalam persamaan setengah reaksi yang dinyatakan. Untuk delapan molekul H2: 8 x 2 = 16 elektron yang dilepaskan, mengalir melalui sirkuit eksternal ke elektroda oksigen.
Check the conclusion and its limits
- Do not put electrons on the reactant side for hydrogen oxidation, allow them to remain in the overall reaction, or say they pass through the electrolyte like they do through a metal wire. Common-tier students still need the overall reaction and fuel-cell evaluation, but these half equations and charge reasoning are Higher-only.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Electrons remain as a product of the complete balanced fuel-cell reaction. This claim is false: Electrons travel through the EXTERNAL circuit and cancel when the half equations combine: H2 releases exactly what O2 consumes. The overall reaction 2H2 + O2 -> 2H2O contains no electrons.
Higher Tier: combine hydrogen fuel-cell half equations: Check atoms and charges separately. The hydrogen half equation has four hydrogen atoms on each side and zero net charge because +4 from H⁺ balances −4 from electrons. The oxygen half equation has two oxygen atoms and four hydrogen atoms on each side, again zero net charge. In this generating cell electrons leave the hydrogen anode through the external circuit and reach the oxygen cathode. The anode is negative and the cathode positive while the cell supplies electricity.
Elektron tetap sebagai produk dari reaksi sel bahan bakar yang setara sepenuhnya.
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Elektron berjalan melalui SIRKUIT EKSTERNAL dan saling meniadakan ketika persamaan setengah reaksi digabungkan: H2 melepaskan persis apa yang dikonsumsi oleh O2. Reaksi keseluruhan 2H2 + O2 -> 2H2O tidak mengandung elektron.
Elektroda tempat oksidasi hidrogen melepaskan elektron dalam sel pembangkit yang disebutkan: tulis istilah teknisnya.
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anoda sel bahan bakar berarti elektroda tempat oksidasi hidrogen melepaskan elektron dalam sel pembangkit yang disebutkan.