[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-110-1-fire-science-026":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-026","fire-110-1-fire-science-026",110,1,26,"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？",{"A":16,"B":17,"C":18,"D":19},"高溫壓縮","等溫壓縮","斷熱壓縮","等熵壓縮","C",null,[],false,"本題考點：壓縮造成溫升而發火的現象名稱,以及斷熱、等溫、等熵三種壓縮過程的區別。\n【正解理由】氣體被快速壓縮時,外界對氣體所作的功來不及以熱的形式散逸至周圍,幾乎全部轉為氣體內能,溫度因而急遽上升,此即斷熱壓縮(絕熱壓縮),其溫度與壓力的關係為 T₂\u002FT₁ =(P₂\u002FP₁)^((k−1)\u002Fk)。柴油引擎的壓燃、高壓氣體鋼瓶急速充填、可燃氣體管線瞬間加壓而發火,都屬於此類由機械能轉為熱能的發火源,故選 C。\n【逐項排除】\n(A) 高溫壓縮:並非熱力學過程的正式名稱,且是以結果描述現象,未說明「熱來不及散失」這個溫升機制。\n(B) 等溫壓縮:過程中溫度維持不變,壓縮功同步以熱的形式排出至外界,依定義不會造成溫升發火,與題意相反。\n(C) 斷熱壓縮:與外界無熱交換,壓縮功全數轉為內能致溫度上升,正確。\n(D) 等熵壓縮:指可逆且絕熱的理想化過程,強調熵值不變;實際急速壓縮伴隨摩擦與不可逆性,熵會增加,火災學描述壓縮發火一律稱斷熱壓縮。\n【記憶點】熱來不及跑掉,功就全變成溫度——斷熱壓縮是機械能發火的代表。","推導的根據是熱力學第一定律 ΔU = Q − W。斷熱條件下 Q = 0,外界對氣體作功 W 為負,故內能 ΔU 增加,而理想氣體內能只與溫度有關,溫度必然上升。搭配理想氣體方程式可推得 PV^k = 定值,以及 T₂\u002FT₁ =(P₂\u002FP₁)^((k−1)\u002Fk),其中 k 為比熱比,空氣約 1.4。代入實例:常溫 300 K、1 atm 的空氣急速壓縮至 10 atm,T₂ = 300 K × 10^0.286 ≈ 579 K,約 306 °C,已足以超過多數潤滑油與部分可燃氣體的自燃溫度。\n\n發火源的分類是本題的上位考點:化學能(氧化熱、分解熱、聚合熱、吸著熱、發酵熱)、電能(電阻發熱、短路、電弧、靜電、雷擊)、機械能(摩擦、衝擊、斷熱壓縮)、熱能(高溫表面、明火、輻射)。斷熱壓縮固定被歸在機械能項下,與摩擦、衝擊並列,考題常以「下列何者屬機械能引起之發火」的形式出現。\n\n易混淆處有二:其一,自燃溫度是物質本身的性質,斷熱壓縮只是把環境推升到該溫度的手段,兩者是因與果的關係,不可互相代換;其二,等熵與斷熱並非同義詞——所有可逆絕熱過程都是等熵,但實際的絕熱過程因摩擦與擾流而熵增,故只能稱斷熱。壓縮比越高、壓縮速度越快,越接近斷熱條件,溫升也越顯著。\n\n可拿來對照的反向現象是節流膨脹:高壓氣體經閥件洩放而急速膨脹時,多數氣體溫度下降(焦耳–湯姆生效應),與壓縮升溫方向相反;但氫氣在常溫下的焦耳–湯姆生係數為負,洩放反而升溫,加上燃燒界限寬、最小引燃能量極低,這是高壓氫氣洩漏容易自行著火的原因之一。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-110-1-fire-science-025","請依據可燃性氣體完全燃燒時的化學理論濃度，計算丙烷的燃燒下限？",25,{"webId":33,"stem":34,"number":35,"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":37,"stem":38,"number":39,"year":11,"session":12},"fire-110-1-fire-science-024","在充足的能量下，下列何種濃度（vol%）的氫氣（H2）為燃燒界限範圍內？",24,{"webId":41,"stem":42,"number":43,"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":45,"stem":46,"number":47,"year":11,"session":12},"fire-110-1-fire-science-023","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？",23,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-110-1-fire-science-029","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？",29,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-026",111,"一公克水完全汽化成水蒸氣，溫度 327℃水蒸氣體積為 V1，溫度 727℃水蒸氣體積為 V2，則 V2\u002FV1 值？",{"webId":58,"year":59,"stem":60,"number":13},"fire-109-1-fire-science-026",109,"閃燃發生時間之影響因素中，通風為其中之一項，請問：A0(H0)1\u002F2 的通風因子公式中，A0 與 H0 各代表何意？",{"webId":62,"year":63,"stem":64,"number":13},"fire-108-1-fire-science-026",108,"乙炔加壓後容易產生分解爆炸，為避免此現象，乙炔鋼瓶常利用浸泡何種溶劑之多孔性物質，使乙炔溶解於其中，防止分解爆炸？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-026",107,"在火勢擴大的過程中，下列那一現象並非成長期的常見特徵？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-026",106,"有一家用延長線，欲連接電子鍋、熱水瓶及微波爐，耗電功率分別為 550 W、1100 W 及 2200 W，請問該延長線至少應具多大之容許電流？（家用電壓為 110 V）",1785123162487]