[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-111-1-fire-science-005":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-111-1-火災學概要-005","fire-111-1-fire-science-005",111,1,5,"在苯中置入油酸鎂等金屬鹼，係採取下列何種防止靜電發生的方法？",{"A":16,"B":17,"C":18,"D":19},"使用除電劑","使用導電性材料","藉中和以防止電荷蓄積","增加周圍空氣相對濕度","A",null,[],false,"本題考點：靜電發生與蓄積的防止對策分類，特別是「除電劑（帶電防止劑）」的定義。\n【正解理由】防止靜電危害的手段可分為接地與等電位連結、使用導電性材料、提高相對濕度、以離子中和電荷，以及在被處理物中添加除電劑等類型。油酸鎂、油酸鈣等油溶性金屬皂加入苯這類導電度極低的非極性溶劑後，可提高液體本身的導電度，使摩擦所生電荷迅速洩漏而不致蓄積，屬於添加除電劑（帶電防止劑）的作法，故選 A。\n【逐項排除】\n(A) 正確。在液體中加入微量金屬皂以提高導電度、縮短電荷鬆弛時間，即為除電劑的典型用法。\n(B) 錯誤。使用導電性材料指的是把容器、配管、輸送帶、地板等器材改為金屬或導電性橡膠、塑膠，改變的是器材而非被處理的液體。\n(C) 錯誤。藉中和防止電荷蓄積是以感應式、電壓式除電器或放射線產生異性離子，中和帶電體表面既有的電荷，作用對象是已帶電物體的表面。\n(D) 錯誤。增加周圍空氣相對濕度是使絕緣體表面吸濕形成水膜以降低表面電阻，對固體表面帶電有效，對苯這類疏水性液體內部的電荷蓄積助益有限。\n【記憶點】加藥入液＝除電劑；換器材＝導電性材料；放異性離子＝中和；加濕＝表面洩漏。","靜電危害的成立要件是「產生電荷→蓄積電荷→放電能量足以引燃→周圍存在爆炸性混合氣」，防止對策即在切斷其中任一環節。常見分類約有五類：一是接地與等電位連結，讓導體上的電荷洩漏至大地；二是使用導電性材料，把容器、配管、輸送帶、地板換成金屬或導電性橡膠、塑膠以降低電阻；三是提高周圍相對濕度，一般以 65% 至 70% 以上為目標，使絕緣體表面形成吸濕水膜而降低表面電阻；四是離子化中和，以感應式、電壓式除電器或放射線產生正負離子中和帶電體電荷；五是添加除電劑，於被處理物中加入微量導電性添加劑，提高其本身導電度。\n本題的油酸鎂屬第五類。苯、甲苯、汽油這類非極性有機溶劑的導電度極低，約在 10⁻¹⁴ S\u002Fm 的量級，輸送、攪拌、過濾、噴射時因界面摩擦所生的電荷幾乎無法自然洩漏，會在液體內部與液面蓄積成高電位，最終以火花放電引燃液面上方的蒸氣。加入油酸鎂、油酸鈣等金屬皂後，液體導電度可提高數個數量級，電荷鬆弛時間大幅縮短，電荷來不及蓄積即已洩漏，這是它被歸類為除電劑的理由。\n易混淆對照必須背清楚：導電性材料改的是器材，除電劑改的是被處理物本身，中和靠外加異性離子，加濕作用在固體表面而非液體內部。選擇題最常把這四者互相對調。\n延伸考點：靜電放電能量 E＝½CV²，與可燃性氣體的最小發火能量比較即可判斷是否足以引燃，甲烷約 0.28 mJ、氫氣約 0.02 mJ，都遠低於人體帶電放電的能量等級。另外降低液體流速、避免自由落下噴濺、加長靜置時間，也屬同一組考點常見的敘述。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-111-1-fire-science-004","日本東京放映所及精神病診所火災起因為縱火，請問汽油在空氣中的燃燒下限為何？",4,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-111-1-fire-science-006","火災成長歷程中，下列何者非閃燃之現象？",6,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-111-1-fire-science-003","實效濕度低於多少時，日本即發布火災警報？",3,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-111-1-fire-science-007","油類火災為何種火災？",7,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-111-1-fire-science-002","有關爆燃與爆轟，下列敘述何者錯誤？",2,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-111-1-fire-science-008","空氣氧之重量占整體之 23%，故 1 公斤碳完全燃燒需要多少空氣？",8,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-114-1-fire-science-005",114,"火災煙毒氣體之危害主要是下列何種氣體？",{"webId":58,"year":59,"stem":60,"number":13},"fire-113-1-fire-science-005",113,"大樓火災常伴隨煙囪效應。所謂煙囪效應是指建築物內部受熱後熱氣流上升，冷空氣由下方填補，使得火災產生的煙霧會快速瀰漫整個建築物的現象。針對以上敘述，下列何者錯誤？",{"webId":62,"year":63,"stem":64,"number":13},"fire-112-1-fire-science-005",112,"鄰二甲苯的閃火點為 157℃，若鄰二甲苯於 157℃時的飽和蒸氣壓為 2.0 mmHg，試求其燃燒下限為何？",{"webId":66,"year":67,"stem":68,"number":13},"fire-110-1-fire-science-005",110,"已知乙烷、乙烯、乙炔的發火能量分別為 a、b、c，則 a、b、c 的大小關係為：",{"webId":70,"year":71,"stem":72,"number":13},"fire-109-1-fire-science-005",109,"下列有關二氧化碳（CO2）滅火劑之敘述，何者錯誤？",1785129966707]