충돌 빈도, 촉매 및 평형 선택
도입됨| English | 의미 |
|---|---|
| equilibrium/ˌiːkwɪˈlɪbrɪəm/ | 평형 |
| catalyst/ˈkætəlɪst/ | 촉매 |
| activation energy/ˌæktɪˈveɪʃn ˈenədʒi/ | 활성화 에너지 |
| tangent/ˈtændʒənt/ | 접선 |
Why can the fastest conditions give a poorer yield?
- An industrial reaction must make product quickly and give enough product at equilibrium 平衡. A hotter reactor can speed an exothermic reaction while reducing its equilibrium yield.
- Separate collision frequency, molecular energy and equilibrium position before deciding which change helps. A catalyst 催化剂 changes the route and the time to equilibrium, not the equilibrium yield at fixed conditions.
Explain successful collisions
- Reaction requires collisions with suitable orientation and enough energy to overcome activation energy 活化能. At fixed temperature, higher concentration or gas pressure makes collisions more frequent; a larger exposed solid surface provides more accessible reaction sites.
- Increasing temperature gives more frequent collisions and, especially, a larger fraction with enough energy. On equal-particle-number energy distributions, the hotter curve is broader with a lower peak and more area beyond the same activation-energy threshold; total area stays the same.
반응하는 기체를 일정 온도에서 압축했습니다.collision theory에 따른 다음 중哪项陈述이 지지되는가?
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입자들이 더 가까워져 충돌 빈도가 증가합니다. 일정 온도는 에너지 분포를 유지하므로, 압축만으로는 에너지적 비율(에너지가 높은 입자의 비율)이 증가하지 않습니다.
Measure a rate at the stated time
- For the same fixed endpoint, relative rate is proportional to $1/t$: 20 s versus 50 s gives rate ratio $(1/20)/(1/50)=2.5$. This comparison assumes the same endpoint amount and matched conditions.
- For gas volume against time, draw a tangent 切线 at the requested point and choose two well-separated points on that tangent. Points (20 s, 30 cm³) and (60 s, 50 cm³) give gradient $\dfrac{50-30}{60-20}=0.50\,\dfrac{\mathrm{cm}^3}{\mathrm s}$. The line from the origin to P gives an average rate, not the instantaneous tangent rate.
With equal endpoint amounts, a halogenoalkane taking 5 s has 36 times the relative rate of one taking 180 s: (1/5)/(1/180) = 36. An endpoint comparison does not prove a complete rate law or isolate bond strength if other conditions differ.
두 일치된 실험이 15 s 및 45 s에서 동일한 종점에 도달합니다. 15 s 실험의 상대적 속도를 45 s 실험의 상대적 속도로 나눈 값을 구하십시오.
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동일한 종점 양에 대해 상대적 속도는 1/시간에 비례합니다. 비율 = (1/15)/(1/45) = 45/15 = 3.
기체 부피 곡선의 접선이 (10 s, 25 cm³) 및 (50 s, 49 cm³)를 지납니다. 이 접선의 기울기를 cm³ per s로 계산하십시오.
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기울기 = 부피 변화량/시간 변화량 = (49 − 25)/(50 − 10) = 24/40 = 0.60 cm³ per s입니다. 곡선과 원점을 잇는 TV 선이 아닌 접선 위의 점을 사용하십시오.
Change the route without changing the energy distribution
- At fixed temperature, a catalyst gives an alternative route with lower activation barriers; the molecular-energy distribution itself stays unchanged. More particles can react, and both forward and reverse reactions become faster.
- Draw catalysed and uncatalysed reaction profiles with the same start/end levels and ΔH. A two-step catalysed route has two peaks and an intermediate valley. A selective route can improve atom economy; faster operation may use less energy, but neither benefit is guaranteed for every catalyst.
고정 온도에서 촉매는 평균 분자 에너지를 높여 생성물의 평형 농도를 증가시킵니다.
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촉매는 온도 분포를 변경하지 않고 경로 장벽을 낮춥니다. 양방향 모두 속도를 높이지만, 고정 조건에서는 평형 위치와 평균 에너지가 변하지 않습니다.
Justify equilibrium shifts and a numerical compromise
- In a closed system at dynamic equilibrium, forward and reverse rates are equal and concentrations stay constant; concentrations need not be equal. For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), increasing pressure favours fewer gas moles, and adding N₂ favours its consumption. For an exothermic forward reaction, cooling favours products but slows reaction.
- Supplied plant data at 450, 550 and 650 K give yields 92%, 76%, 46% and relative rates 0.040, 0.60, 2.5. If yield must be at least 70% and rate at least 0.50, only 550 K meets both. These requirements justify that choice; the table alone does not establish a global economic optimum.
Pressure does not shift equilibrium when the two gas sides have equal mole totals. A catalyst does not favour products at equilibrium. Constant concentration means continuing reactions balance, not that molecular reactions stop.
Use collision theory for rate, tangent or fixed-endpoint data for measurement, and reversible-reaction reasoning for yield. Test industrial choices against the actual numerical constraints.
450/550/650 K에서 수율은 92/76/46%이고 상대적 속도는 0.040/0.60/2.5입니다. 수율 ≥70% AND 속도 ≥0.50를 만족하는 것은?
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450 K는 속도 제한을 위반하고, 650 K는 수율 제한을 위반합니다. 오직 550 K만이 두 조건을 모두 충족합니다. 제공된 제한은 보편적인 경제적 최적점을 설정하지 않습니다.