[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-113-1-fire-science-023":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-113-1-火災學概要-023","fire-113-1-fire-science-023",113,1,23,"根據 Burgess-Wheeler 定理，若丙烷的燃燒下限為 2.2%，其燃燒熱約為多少 kcal\u002Fmole？",{"A":16,"B":17,"C":18,"D":19},"23.3","115.4","233.6","480.9","D",null,[],false,"本題考點：Burgess-Wheeler 定理，燃燒下限與莫耳燃燒熱的乘積約為定值，由下限反推燃燒熱。\n【正解理由】依 Burgess-Wheeler 定理，同系列烴類氣體的燃燒下限（以體積百分比表示）與其莫耳燃燒熱的乘積接近一個常數，約為 1,058 kcal／mole，教科書多寫成 1,050 至 1,060 之間。丙烷的燃燒下限為 2.2％，以定值除以下限即得莫耳燃燒熱約 481 kcal／mole，與選項的 480.9 相符。故選 D。\n【逐項排除】\n(A) 23.3 代回定理得 23.3×2.2≈51，與約 1,058 的定值相差二十倍以上，量級明顯不符。\n(B) 115.4 代回定理得 115.4×2.2≈254，僅約定值的四分之一。\n(C) 233.6 代回定理得 233.6×2.2≈514，約為定值的一半，仍差一倍。\n(D) 480.9 代回定理得 480.9×2.2≈1,058，與定值相符，為正解。\n【演算步驟】Burgess-Wheeler 定理：燃燒下限（％）×莫耳燃燒熱（kcal／mole）≈1,058；莫耳燃燒熱＝1,058÷2.2＝480.9 kcal／mole。\n【記憶點】下限乘燃燒熱約等於 1,058，燃燒下限愈低者其莫耳燃燒熱愈大。","Burgess-Wheeler 定理源自對飽和烴系列燃燒下限的實驗歸納：把各烴類的燃燒下限乘上其莫耳燃燒熱，所得乘積落在約 1,050 至 1,060 kcal／mole 的狹窄範圍內。其物理意義是火焰要能自行向未燃混合氣傳播，單位體積混合氣所能釋放的熱量必須跨過一個門檻，使火焰面溫度足以引燃相鄰的混合氣；因此燃燒熱愈大的分子，只需愈低的濃度就能跨過門檻，兩者自然成反比。\n可用甲烷驗證：甲烷燃燒下限約 5％、莫耳燃燒熱約 212 kcal／mole，乘積約 1,060，與定值吻合。適用限制也常入題：本定理主要適用於飽和烴，對含氧、含鹵素或含硫的化合物偏差較大，氫氣與一氧化碳亦不適用，作答時若題目給的是這類氣體，不宜直接套用。\n單位換算方面，1 kcal 約等於 4.186 kJ，故 480.9 kcal／mole 約為 2,013 kJ／mole，與丙烷的實測燃燒熱屬同一量級，可作為答案合理性的快速檢核。\n相關公式一併整理。其一為溫度修正式，燃燒下限隨溫度上升而下降，一般寫為 Lt＝L25×〔1－0.000721×(t－25)〕，說明高溫環境中氣體更易達到可燃濃度。其二為勒沙特列公式，混合可燃氣體的燃燒下限 L＝100÷Σ(Vi／Li)，其中 Vi 為各成分的體積百分比、Li 為各成分的燃燒下限，常與本定理合併命題。其三為危險度 H＝(U－L)／L，以燃燒範圍寬窄相對於下限的比例評估氣體的危險性。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-113-1-fire-science-022","一物體在 27℃時輻射出的能量為 E，則當溫度升高到 627℃時輻射出的能量變為多少？",22,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-113-1-fire-science-024","木材加熱到引火溫度時，可燃性氣體析出量迅速增加，木材的引火溫度約為多少℃？",24,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-113-1-fire-science-021","依建築物火災 t2 成長理論，若釋熱率達 1 MW 需時間 100 秒，則釋熱率達 4 MW 所需時間為多少秒？",21,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-113-1-fire-science-025","容器內氣體受到壓縮造成內部溫度升高，進而發火，此現象稱為？",25,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-113-1-fire-science-020","依據「滅火器認可基準」對於火災分類之內容，下列物質燃燒時，何者屬於 A 類火災？",20,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-113-1-fire-science-026","有關燃燒上下限之敘述，下列何者正確？",26,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-112-1-fire-science-023",112,"在最小發火壓力以上，可燃性氣體的最小發火能量，會隨著下列那一種條件改變而下降？",{"webId":58,"year":59,"stem":60,"number":13},"fire-111-1-fire-science-023",111,"建築物起火後，對於防止火焰由下層窗戶往上層延燒，下列敘述何者錯誤？",{"webId":62,"year":63,"stem":64,"number":13},"fire-110-1-fire-science-023",110,"請問 2 公斤的氫氣（H2）完全燃燒，所需要的理論空氣量為多少公斤？",{"webId":66,"year":67,"stem":68,"number":13},"fire-109-1-fire-science-023",109,"若要看清某一物體，該物體與其背景間有一定之對比度。對比度之計算：C=(B\u002FB0)-1，有關對比度下列何者正確？",{"webId":70,"year":71,"stem":72,"number":13},"fire-108-1-fire-science-023",108,"乙醇在閃火點時的飽和蒸汽壓為 25 mmHg，則乙醇在常壓下的燃燒下限約為何？",1785129966311]