27. Eating too much fat can______ heart disease and cause high blood pressure.
A. result from B. contribute to C. attend to D. lead in
26. You said boys were cleverer than girls. That is _______ I disagree.
A. what B. where C. which D. why
25. --- Nancy is not coming tonight. --- But she______!
A. promises B. promised C. will promise D. had promised
24. The bell______ the end of the period rang and we had to stop our discussion.
A. indicating B. indicated C. to be indicated D. being indicated
23. ---I hear John refused to tell the truth and was taken away by the police.
--- Where did you _______?
A. pick that up B. put that up C. make that up D. take that up
22. ---Are all telephone numbers_______ in the directory? --- Yes, all ________ Jane’s.
A. listed; including B. listed; included
C. including; includes D. being listed; being included
第一節、單項選擇(15分)
21._____ we were worried about was _______ they could manage to control the pollution.
A. That; how B. That; whether C. What; that D. What; whether
4.(湖北省武漢市教科院2009屆高三第一次調考)某化學興趣小組用下圖所示裝置測定鋁鎂合金薄片中鋁質量分數和鋁的相對原子質量。(鐵架臺等固定裝置已略去)
回答下列問題:
(1)實驗前檢查裝置氣密性的方法是 。
(2)實驗前,先將鋁鎂合金薄片用砂紙打磨,其目的是 。
(3)A中試劑為 。
(4)經檢查裝置氣密性完好后,將藥品和水裝入各儀器中,連接好裝置,需進行的操作還有:①記錄C中的液面位置;②將B中剩余固體過濾、洗滌、干燥、稱重;③待B中還有氣體產生,恢復至室溫后,記錄C的液面位置;④由A向B中滴加足量試劑。上述操作的順序是 (填序號);記錄C的液面位置時,除視線平視外,還應 。
(5)B中發生反應的化學方程式為 。
(6)若實驗用鋁鎂合金薄片的質量為m g(打磨后稱量),測得產生氣體的體積為V ml.(已換算為標準狀況),B中剩余固體的質量為n g,試計算鋁的相對原子質量。
(7)合金薄片中鋁的質量分數的表達式為 。
[解析](1)方法一:往裝置D中加入一定量的水,關閉分液漏斗活塞,用手捂住裝置B一段時間,如果裝置C和裝置D中形成穩定的液面差,說明裝置不漏氣,否則裝置漏氣。
方法二:先關閉漏斗活塞后,再向裝置D中加入一定量的水,如果裝置C和裝置D中形成穩定的液面差,說明裝置不漏氣,否則裝置漏氣。
(2)除去鋁鎂合金表面的氧化膜。
(3)NaOH溶液(或KOH溶液或Ba(OH)2溶液)
(4)①④③② 使D和C的液面相平
(5)2Al+2NaOH+2H2O 2NaAlO2+3H2↑
(6)合金中合鋁的質量為
鋁與NaOH溶液反應析出氫氣的物質的量為
設合金中鋁的物質的量為
2Al+2NaOH+2H2O 2NaAlO2+3H2↑
2 3
則鋁的摩爾質量為
故鋁的相對原子質量為
(7)(答案為
時,不給分)
[答案](1)----(5)見解析,(6) (7)
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