[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-022":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":27,"sameNumber":52,"hasEssay":26},"火災學概要","fire-science","火災學 · Fire Science","火災學",{"id":9,"webId":10,"year":11,"session":12,"subject":4,"number":13,"stem":14,"options":15,"answer":20,"answerNote":21,"images":22,"imagesPending":23,"lawTimestamp":11,"explanation":24,"explanationDeep":25,"freq":12,"indexable":26},"fire-107-1-火災學概要-022","fire-107-1-fire-science-022",107,1,22,"燃燒塔每分鐘需消耗 5.8 kg 之丁烷（C4H10），請估算在 NTP（25℃，1 大氣壓）之條件下，此燃燒塔每小時所需之燃燒理論空氣體積（LV）約為下列何者？",{"A":16,"B":17,"C":18,"D":19},"1250 m3","3600 m3","4540 m3","5600 m3","C",null,[],false,"本題考點：由完全燃燒反應式求理論空氣量，並以 NTP 條件下的莫耳體積換算成體積流量。\n【正解理由】丁烷完全燃燒式為 C₄H₁₀＋6.5O₂→4CO₂＋5H₂O，每 1 莫耳丁烷需 6.5 莫耳氧；空氣中氧約占 21%，理論空氣量即理論氧量除以 0.21。以丁烷分子量 58 g\u002Fmol 換算莫耳流量，再套 NTP（25℃、1 atm）莫耳體積 24.45 L\u002Fmol，得每小時約 4540 m³，故選 C。\n【逐項排除】\n(A) 1250 m³：此空氣量僅夠燃燒約 1.6 kg\u002Fmin 的丁烷，與題給燃料量不符。\n(B) 3600 m³：對應約 4.6 kg\u002Fmin 的丁烷，仍低於題給的 5.8 kg\u002Fmin。\n(C) 4540 m³：與反應式配平後求得的理論空氣量一致，正確。\n(D) 5600 m³：對應約 7.2 kg\u002Fmin 的丁烷，超出題給燃料量。\n【演算步驟】n＝5800 g\u002Fmin÷58 g\u002Fmol＝100 mol\u002Fmin → O₂＝100×6.5＝650 mol\u002Fmin → 空氣＝650÷0.21≈3095 mol\u002Fmin → 每小時 3095×60≈185700 mol → V＝185700 mol×24.45 L\u002Fmol≈4540000 L＝4540 m³。\n【記憶點】先配平取氧莫耳數，除以 0.21 得空氣，再乘 24.45 L\u002Fmol。","理論空氣量的計算有固定套路：先寫出完全燃燒反應式並配平，碳全部變二氧化碳、氫全部變水；碳氫化合物 CₘHₙ 所需氧莫耳數即 m＋n\u002F4，丁烷 C₄H₁₀ 代入得 4＋10\u002F4＝6.5，正是本題係數的由來。接著除以空氣中氧的體積分率 0.21 得理論空氣莫耳數，最後乘莫耳體積換成體積。\n莫耳體積是本題最容易失分的地方：STP（0℃、1 atm）為 22.4 L\u002Fmol，NTP（25℃、1 atm）則由理想氣體方程式 V＝RT\u002FP＝0.082×298÷1≈24.45 L\u002Fmol。題目寫明 25℃ 卻習慣性套 22.4，答案會偏低約 9%，剛好落在另一個選項附近，這是命題者設下的陷阱。\n質量法也要會：每 58 公克丁烷需氧 6.5×32＝208 公克，空氣含氧質量分率約 23.2%，故需空氣約 897 公克，理論空燃比約 15.5，與汽油的 14.7 同一量級，可互相參照記憶。\n單位換算的路徑要走順：質量流量除以分子量得莫耳流量，莫耳流量乘化學計量係數得氧莫耳流量，除以 0.21 得空氣莫耳流量，乘莫耳體積得體積流量，最後把公升除以 1000 換成立方公尺、每分鐘乘 60 換成每小時。本題最後一步 185700 mol×24.45 L\u002Fmol≈4.54×10⁶ L，正好是 4540 m³，若忘了乘 60 會只剩約 75.7 m³，數量級一看就知道錯。\n延伸考點：實際燃燒器不會剛好用理論空氣量，過剩空氣率與空氣比（實際空氣量／理論空氣量）是常見的計算延伸，空氣比大於 1 為貧油燃燒、小於 1 為濃油燃燒而易生一氧化碳與煙。丁烷屬液化石油氣主成分之一，比重大於空氣而易在低處滯留，其爆炸範圍約 1.8% 至 8.4%，與理論混合比對照可看出完全燃燒濃度落在爆炸範圍中段偏低處，這也是為何燃燒塔須維持穩定供風的原理。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-021","油罐車在灌裝作業中，其累積電壓為 16 kV（其體積為 20 m3，電容為 1000 pF），試估算此作業所產生靜電能量為多少毫焦耳（mj）？",21,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-023","熱傳導之熱流動方向為何？",23,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-020","為防止由窗口噴出的火焰向大樓上層延燒，下列措施何者錯誤？",20,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-024","容易著火之燃料具下列何種特性？",24,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-019","電線因火災燒熔而短路所形成之熔珠，稱為下列何者？",19,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-025","下列何者並非複燃（backdraft）發生之原因？",25,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-022",111,"連棟式木造建築物引發火災，消防隊射水同時拆除未受火勢波及的房屋，請問其採取的滅火方法係下列何者？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-022",110,"火災中所產生的輻射熱量與下列何者成正比？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-022",109,"預防過氧化丁酮之火災爆炸時，下列何種原則正確？",{"webId":66,"year":67,"stem":68,"number":13},"fire-108-1-fire-science-022",108,"物體在 327℃時的輻射強度為 E，則當溫度升高到 927℃時的輻射強度為何？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-022",106,"水的滅火效果，下列何者正確？",1785123163695]