動的平衡：等しい速度、反応の継続
導入済み| English | 意味 |
|---|---|
| reversible reaction/rɪˈvɜːsɪbl rɪˈækʃn/ | 可逆反応 |
| equilibrium/ˌiːkwɪˈlɪbrɪəm/ | 平衡 |
What would explain this observation?
- A closed reaction vessel can show constant composition while particles still react in both directions. Equality of rates keeps the overall amounts unchanged.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- When a reversible reaction 可逆反应 occurs in apparatus preventing escape of reactants and products, equilibrium 平衡 is reached when forward and reverse reactions occur at exactly the same rate. The state is dynamic: both directions continue. At fixed conditions the amounts of reactants and products stay constant, but they need not be equal. A closed system prevents loss of matter; it does not necessarily prevent energy transfer to maintain a set temperature.
- equilibrium: A state with equal forward and reverse reaction rates; reversible reaction: A reaction whose products can react to reform the original reactants.
動的平衡において、必ず等しくなるのはどの組み合わせか？
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
平衡状態は動的です。正反応と逆反応が同じ速度で継続するため濃度は一定です。濃度自体は通常異なり、質量が等しいことは関係ありません。
各専門用語を正確な意味と対応させよ。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
関連する物理量やプロセスを区別するために定義を使用せよ。
Choose evidence that can test it
- Beginning with mostly reactants, the forward rate may be high while the reverse rate is initially low. As products accumulate, reverse reaction becomes possible more often until the rates match under the stated model. A reaction-rate graph should show convergence to the same non-zero rate. A composition graph can level off at different reactant and product amounts. Identify which quantity is on the axis before claiming two curves must meet.
- Use an original particle-count model or supplied data with fixed conditions and no matter lost. Count forward and reverse events over equal time windows. Their difference gives net change for a one-to-one A ⇌ B model. Do not build a sealed heated chemical apparatus to demonstrate the idea; safe school demonstration arrangements require approved containment and temperature control. A count model illustrates balance without proving a particular real chemical rate law.
この場合、調査やモデルをより妥当にする2つの習慣は何か。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
条件や仮定を明記することで他者が正確に再現でき、根拠となる証拠を記録することで結論を検証できます。相反する結果を隠すと、誤った結論を疑う証拠を失いますし、単一の測定でより広い主張を成立させることはできません。
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: in a closed A ⇌ B model, 18 forward and 18 reverse events occur in one second. Net B change=18−18=0 even though 36 reaction events occur. If 70 A and 30 B particles remain on average, these unequal amounts are compatible with equilibrium. At an earlier interval with 20 forward and 12 reverse events, net B increases by eight and the model is not yet at equilibrium.
In a one-to-one A ⇌ B model, 22 forward and 22 reverse events occur in one second. Find net change in B count. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
1対1の A ⇌ B モデルにおいて、1秒間に 22 回の正方向反応と 22 回の逆方向反応が起こります。B の個数の純変化量を求めなさい。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
結果は 0 粒子です。既知：22 正反応と 22 逆反応が每秒、1:1 A-Bモデルで発生。Bの正味変化 = 正反応 − 逆反応 = 22 − 22 = 0 粒子每秒。36回の反応が起こっても個体数が変わらないのは「動的」です。
Check the conclusion and its limits
- Constant amounts do not mean particles are motionless or reaction has stopped. A steady open-flow system can also have constant measured amounts, so constancy alone does not establish closed-system equilibrium. Equal mass, concentration and molecule count are not the required equality: rates are. Condition-change predictions are separately Higher-only.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
At dynamic equilibrium both chemical reactions have stopped. This claim is false: Dynamic equilibrium means the reactions keep running in both directions at matching rates. Everything continues at the particle level; only the observable NET change is zero.
Dynamic equilibrium: equal rates, continuing reactions: Beginning with mostly reactants, the forward rate may be high while the reverse rate is initially low. As products accumulate, reverse reaction becomes possible more often until the rates match under the stated model. A reaction-rate graph should show convergence to the same non-zero rate. A composition graph can level off at different reactant and product amounts. Identify which quantity is on the axis before claiming two curves must meet.
動的平衡においては、両方の化学反応は停止している。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
動的平衡とは、両方向の反応が一致した速度で継続していることを意味します。粒子レベルではすべてが継続しており、観測可能な正味の変化だけがゼロです。
正方向と逆方向の反応速度が等しい状態：技術用語を記せ。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
平衡とは、正方向反応速度と逆方向反応速度が等しい状態を意味する。