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問題的種類

英文 大學

哪一個段落沒有主題句? 我覺得是第一個,對嗎? 要怎麼替這個段落寫出主題句呢?

2 Despite different home cultures and countries, international students' main overall motivation is the desire get out on their own, to carve out a new direction in their lives. "Foreign students" do not casually abandon the comforts of family and cultural ties; they have done their homework on Canadian schools. All their preparation, though, cannot prepare them for the loneliness and ongoing difficul- ties they face, from cold winters to financial issues related to the higher tuition fees they must pay. Some students, though, emigrate to escape those same tight- knit families and bonds that others find so painful to leave behind. A Macleans "On Campus" report notes that family expectations may be opposed to students' visions for themselves and lead them to reject accepted values and career paths in their hometowns and countries. Csilla, a web-design student at Waterloo admits, "I was always supposed to enter my family's restaurant business in Budapest, but I felt suf- focated even working part-time as a server. Web design is my passion, and I wanted 12: CAUSE OR EFFECT [- a completely fresh start, something that is completely my own ("International Stu- dents"). Finding independent paths to their own dreams is the key here, whether students choose those paths as a result of personal ideals or as a reaction to pre-set future plans.

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化學 高中

請問第22題的B和D該怎麼解釋

氧化教行 4H2C 比杜月碗酸巧的硫酸亞鐵(FeSO4式量=152)後,將其溶於 20 毫升、0.5M 的熱硫酸溶液中,隨即 以 0.001M 的KMnO4溶液滴定。當加入 25.00 毫升 KMnO4時,達滴定終點。已知滴定反應式如下:(A) (c) (D)已年最高氣 x MnO4-(aq)+Fe2+(aq)+Y+(aq) → Mn²+(aq)+Fe2+(aq)+H2O(l) (係數未平衡) MnO4 + 5FE+ + 8H²7Mn²+ + 5 Fe + 假設該硫酸亞鐵中之不純物,不含上列反應式中的任何離子,試問下列有關該滴定的敘述,哪些正確?(A)將係 數平衡至最簡整數後,HO 前之係數為8(B)溶液中的[Fe²]恆等於5[MnO4](C)該硫酸亞鐵的純度約為20%(重 量百分率)(D)為提供 H(aq), 1.0M 的 HCl(aq)是適合的酸源(E)溶液中的[Fe*]恆等於 5[Mn²+] 18. 將一顆市售維他命C(分子式 CH8O6,分子量=176)加水使其完全溶解,配製成 100mL 溶液。取此溶液 20mL 置 入一錐形瓶中,加入適量的澱粉液作為指示劑,需用 12 mL 的 0.10 M 碘液滴定,達到滴定終點,維他命C與碘的 化學反應式如下:C6H8O6(aq)+2(aq) C6H6O6(aq)+2H*(aq)+21 (aq)下列敘述,哪些正確?(A)滴定終點時錐 形瓶內溶液的 pH 值上升(B)反應中,碘為氧化劑(C)反應中每莫耳維他命C分子釋出2莫耳電子(D)到達滴 定終點的瞬間,溶液顏色由藍色變為透明無色(E)此顆市售維他命C中約含有 500 mg 的維他命C19B)N2+3H29 TH 1哈伯法) 19.下列哪一反應的氣態產物僅能使用向下排氣法收集?(A)加熱亞硝酸鈉與氯化銨(B)在高溫、高壓下,以細鐵粉人 催化氮氣與氫氣(C)氫化鈉溶於水(D)氫氣與氣氣反應(E)銅與濃硝酸反應17A) AH4Cl+NaNO2 → NaCl+2H2 20.下列三個反應式中的W、X、Y與Z分別為四個金屬元素的代號,已知下列三個受應均能幫若進行: H₂ Na OH X+YCl2 XC1₂+Y; Y+ZC12 YCl2+Z;Z+WCl2 → ZCl2+20(C) W是最弱的還原到 試依據以上三個反應式,推測下列何者正確?(A)X是最強的還原劑(B)XCh是最弱的氧化劑(C)Z是最強的 還原劑(D)ZC是最弱的還原劑(E)WC是最強的氧化劑20.氧化還原方向:張氧+強還→弱置+弱氧 21. 下列有關化學電池的敘述,哪些正確?(A)化學電池是利用非自發性氧化還原反應來產生電流的裝置(B)碳鋅電 池的電解液中,NH4Cl與MnO2均發生還原反應(C)隨著鉛蓄電池放電,電解液的pH 值會降低(D)鉛蓄電池放 電時,陽極之重量會減(E)鉛蓄電池中的鉛極,不管在放電或充電,都扮演負極的角色減少PH↑, 但不 22.下列有關氫-氧燃料電池之敘述,何者正確?(A)燃料電池把化學能轉換成電能的效率比傳統火力發電的能量轉換 功率高(B)每消耗1莫耳氫氣,可產生4法拉第電量(C)放電時,電池中之電解液濃度增加(D)反應物耗盡導致 無法供電時,應於陽極反應槽中填充氧氣(E)不論電解液的酸鹼性,氫氧燃料電池的全反應式均為2H2(g)+O2(g) 2H2O(l) 陽極為子被氧化產生 等莫耳敬的Pb504, 重量增加 →>>>> NO3 + GulKNO3)2+2502+2H2O 美氣法:02. → 第2頁, 陰極為被還虎 21. (B12Mn0215) + 2NH4Cl(aq) + Zn(s) → Zn(NH3)2Cl2+Mn2O3(s)+H2O(e) (E) 放: PB+60元 +2H2309 +2Pb3e4+² 逆反應

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