[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-110-1-fire-science-029":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-110-1-火災學概要-029","fire-110-1-fire-science-029",110,1,29,"工廠使用之乙炔（C2H2），為防止爆炸引起火災，常利用裝有某化學物質與多孔性物質充填物之鋼瓶加壓保存，請問該化學物質為何？",{"A":16,"B":17,"C":18,"D":19},"氮氣（N2）","氦氣（He）","丙酮（CH3COCH3）","二氧化碳（CO2）","C",null,[],false,"本題考點：溶解乙炔鋼瓶的充填原理——乙炔加壓易生分解爆炸,須以溶劑溶解後貯存。\n【正解理由】乙炔分子含碳碳三鍵,本身為吸熱化合物,單獨加壓至約二個大氣壓以上或受衝擊、局部高溫時,不需要氧氣也會自行分解為碳與氫並放出大量熱,形成分解爆炸。因此工業用乙炔不以純氣體高壓充填,而是先在鋼瓶內填滿矽藻土、活性碳一類多孔性物質,再浸潤丙酮,使乙炔大量溶解其中,以溶解乙炔的形態安定貯存,故選 C。\n【逐項排除】\n(A) 氮氣為惰性氣體,只能稀釋或作為封氣使用,對乙炔幾乎不具溶解能力,無法把大量乙炔留在瓶內。\n(B) 氦氣同屬惰性氣體且分子極小,在液體中的溶解度是所有氣體裡最低的一群,更不可能作為溶解介質。\n(C) 正確。丙酮在常溫常壓下每單位體積可溶解約二十餘倍體積的乙炔,溶解量並隨壓力升高而增加,正是鋼瓶採用的溶劑。\n(D) 二氧化碳用於惰性化與滅火,本身即為氣體,無法扮演液態溶劑的角色,也不能抑制乙炔的分解反應。\n【記憶點】乙炔怕分解爆炸,鋼瓶裡是「多孔性物質＋丙酮」,靠溶解而不是靠高壓。","乙炔的危險性可從三個層面理解。第一是分解爆炸:碳碳三鍵的生成熱為正值,分解為固體碳與氫氣時放熱甚鉅,屬於不需要氧化劑即可自持的化學性爆炸,壓力愈高、管徑愈大愈容易由局部起爆傳播為整管分解,所以乙炔的充填壓力必須壓在很低的範圍。第二是燃燒範圍極寬:乙炔在空氣中的爆炸界限約為 2.5% 至 81%,上限之高在常見可燃氣體中名列前茅,微量洩漏即落入範圍內。第三是與金屬的反應:乙炔遇銅、銀會生成極敏感的乙炔銅與乙炔銀,受衝擊即爆,因此相關配管器材避開高含銅材質。\n鋼瓶內兩種填充物分工明確。多孔性物質(矽藻土、活性碳、木炭與水泥的燒結體)把瓶內空間切割成無數細小孔隙,即使某處發生分解,火焰也難以在細孔中傳播,等於內建阻火作用,同時支撐溶劑不致晃動;丙酮則負責溶解。氣體在溶劑中的溶解量大致遵循亨利定律,溶解量與該氣體分壓成正比,因此加壓後瓶內可貯存的乙炔量遠大於同體積的純氣體。也因為溶劑會隨氣體一起帶出,乙炔瓶必須直立使用,橫放會使丙酮流失。\n數值上,乙炔瓶的充填壓力約為每平方公分十五公斤,遠低於氧氣瓶的每平方公分一百五十公斤;兩者外觀相近而壓力相差約十倍,是考題常設的對比點。乙炔與氧混合燃燒的火焰溫度可達約攝氏三千三百度,為氣體熔接的主要熱源,也反映其反應放熱之劇。\n易混淆對照:分解爆炸(乙炔、環氧乙烷、聯胺)不需空氣,氧化爆炸(一般可燃氣體)必須與空氣形成混合氣;前者的抑制方向是降壓、阻火與稀釋,後者則是把濃度控制在爆炸範圍之外。延伸考點常見於氣體分類題,以及以乙炔 2.5% 的下限代入勒沙特列公式求混合氣體爆炸下限的計算題。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-110-1-fire-science-028","下列有關電器用品「焦耳熱」之敘述，何者錯誤？",28,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-110-1-fire-science-030","某建築物火場產生大量煙霧，正向煙囪效應在中性帶以上 10 公尺處的壓力差為 12 Pa，若建築物內、外的溫度差不變，請問中性帶以上 20 公尺處的壓力差為何？",30,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-110-1-fire-science-027","某建築物的插座電壓為 110 伏特，在其延長線上的插座同時插 880 瓦的電磁爐、110 瓦的電風扇及 1100 瓦的電熱器，請問該延長線之額定電流至少需多少安培？",27,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-110-1-fire-science-031","有關影響粉塵爆炸的因素，下列何者錯誤？",31,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-110-1-fire-science-026","易燃性氣體受到壓縮後溫度會有升高的狀況發生，可能會發火導致火災的發生，此現象為何？",26,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-110-1-fire-science-032","有關爆炸性物質之特性，下列何者正確？",32,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-029",111,"建築物內部裝潢材料對閃燃時間（F.O.T.）的影響，下列敘述何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-109-1-fire-science-029",109,"有關防火塗料敘述，下列何者錯誤？",{"webId":62,"year":63,"stem":64,"number":13},"fire-108-1-fire-science-029",108,"煙霧的流動為由高壓處往低壓處流，因此加壓造成壓力差可以有效控制煙霧流動。若於一安全梯間流入體積流率為 Q(m3\u002Fs)的空氣，形成 P 的壓力差，現欲將壓力差提高到 2P，則流入的空氣體積流率應為多少？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-029",107,"下列何者並非學校實驗室火災之特性？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-029",106,"一般而言，區劃空間火災中引發閃燃時，樓地板最低輻射熱通量值約為何？",1785123162508]