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S(s) + O2(g) = SO2(g)From the perspective of entropy, the first one will be favoured because of less decrease in entropy(disorder)
2S(s) + 3O2(g) = 2SO3(g)
Which one is more likely to occur?
From the thermodynamic perspective, S=O bond strength should be weaker than O=O bond strength, so it is less likely that 3 S=O will be present in the same molecule,although the additional resonance stabilisation effect may be taken into account for SO3.
If the reaction is a single step reaction, then it is probably kinetically unlikely that 5 molecules from the reactant side will collide with each other to form the desired products.
However, kinetic control and thermodynamic control may help us achieve selectivity between the two pathways by tuning the temperature of interest which affects the reversibility of the reaction.
如果我考緊midterm會咁答,有d嘢無absolute answer,只係得reasonable answer,姐係合理地吹都可以,直到你去做實驗confirm。
利申:大學organic chem /inorganic chem A+ DSE chem 5**
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constant pressure一般係指空許個container expand volume
當system內gas volume increase(不論係reaction產生gas定exothermic process令system內既空氣expand),會有work done by system to surroundings令活塞向外推
最後令system pressure同外界既pressure相等,亦即係樓上提過既唔fix V而fix P
至於你話neutralization既case 因為做實驗時唔會用太多既acid / alkali (因為最後都係計kJ mol-1 用多都無意義) 放出既熱通常唔多 air expand造成既work done好有限 正路都會忽略
standard condition係指environment
但reactant本身都要standard state (即係C要graphite / O要O2)