初二科学试验题
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1溶解:黄酒 食盐
不溶:菜油 面粉
2溶液
悬浊液 面粉
乳浊液 菜油
3 黄酒 食盐 不分层(它们是溶液,有稳定性)
面粉 菜油 分层(它们是浊液,不稳定)
绛旓細锛1锛夌敤澶瑰瓙澶逛綇A锛岋紙闃叉H2杩囧杩涘叆锛夛紙2锛夌伀鐒板垰濂界唲鐏椂锛屾病鏈夊強鏃跺す浣廇锛屾垨瑁呯疆姘斿瘑鎬т笉濂 锛3锛変笉璁ゅ悓锛屽洜涓篊O鐐圭噧鍚庣敓鎴怌O2姘斾綋浣撶Н鍙嶅簲鍓嶅悗鍩烘湰涓嶅彉
绛旓細鍦ㄩ厭绮句腑鎮诞 璇存槑瀵嗗害璁$殑瀵嗗害涓0.8g/ml(閰掔簿瀵嗗害)鏀惧湪姘撮噷鏃讹紝鏍规嵁娴姏鍏紡 锛圠-h1锛*1g/ml=L*0.8g/ml锛圠涓哄鏂欑闀垮害锛夎В寰楋細 h1=0.2L h2=0.4L 鎵浠ユ斁鍏ュ緟娴嬫恫浣撴椂锛歀*0.8g/ml=(L-h2)*p p=4/3 g/ml
绛旓細闃冲厜涓嬬殑璇曠娑查潰浣 椤甸潰杩涜钂歌吘浣滅敤 娌归伄浣忎簡椤甸潰鐨勬皵瀛斾笉鑳借繘琛岃捀鑵句綔鐢 鑰屼笖娌℃湁闃冲厜鐓у皠 璇存槑妞嶇墿鍦ㄩ槼鍏変笅杩涜鍏夊悎浣滅敤娑堣楁按 鍙﹀杩樿繘琛岃捀鑵句綔鐢
绛旓細濡傚浘銆
绛旓細涓:璇ラ浂浠舵敼涓洪摑闆朵欢鍚庝綋绉笉鍙橈紝鍗砎閽=V閾 m閾+104kg/蟻閽=m閾/蟻閾,m+104kg/7.9脳1000kg/m³=m閾/2.7脳1000kg/m³寰梞閾=54k 浜:(1)鍐姣忕摱鐨勮川閲:m鍐=蟻鍐瑅0.88脳10³脳0.015kg=13.2kg,鍐姣忓崈鍏嬩环閽变负:55/13.2=4.17鍏 澶忓姣忕摱鐨勮川閲:m澶=0.8脳...
绛旓細(1)F娴=蟻gV=1*10^3*10*100*10^(-6)=1N (2)姘寸殑娴姏?(3)搴曢潰绉100/2=50cm^2,姘翠綋绉50*10=500cm^3 姘撮噸鍔500*10^(-6)*1*10^3*10=5N 鎵浠ュ簳闈㈠彈鍔5+3=8N 鍘嬪己涓8/500*10^(-6)=16000Pa
绛旓細璁捐瀹為獙瑕侀伒寰袱涓熀鏈師鍒:鍗冲崟涓鍙橀噺鍜屽鐓,鍥犳鏈疄楠屽彲璁捐涓ょ粍.绗竴缁:鍒嗗埆鍙栦竴鐩嗙敓闀挎甯哥殑浠欎汉鎺屽拰涓鐩嗛様鍙舵鐗,缂栧彿A鍜孊.姣忛棿闅斾竴娈垫椂闂村悜A鐩嗗拰B鐩嗘祰绛夐噺鐨勫ぇ閲忕殑姘.(棰勬祴:浠欎汉鎺屾鎺,闃斿彾妞嶆牚鐢熼暱姝e父.璇存槑浠欎汉鎺屼笉閫傚簲姘寸幆澧冭岄様鍙舵鏍傚簲姘寸幆澧)绗簩缁:鍒嗗埆鍙栦竴鐩嗙敓闀挎甯哥殑浠欎汉鎺屽拰...
绛旓細3銆佹牴鎹噸鍔=娴姏 鎺ㄥ嚭锛氬簲涓75g鐨勯噸鍔涳紝鍐嶅姞25g鐨勯噸鍔 4銆佽閾佺殑瀵嗗害涓合侀搧=7.9.灏辨槸璇存按瀵归搧鍜屾湪鍧楃殑娴姏涔嬪拰=閾佸拰鏈ㄥ潡鐨勯噸鍔涗箣鍜岋紙V閾+75锛*g=锛圴閾*7.9+50锛塯 鎺ㄥ嚭锛歏閾=3.62锛堜繚鐣欎袱浣嶏級鎺ㄥ嚭锛氶搧鐨勮川閲28.6閲嶅姏锛28.6g 濂界疮鍟婏紝濂藉骞存病鍋氳繖鏍风殑棰樹簡鍛靛懙濡傛灉鏈夐敊璇瑙佽皡锛...
绛旓細V瀹=m/蟻=1*10^-4 G=2.7N F娴=G=2.7N=蟻姘磄V= V=2.7*10^-4 V-V瀹=V绌=1.7*10^-4
绛旓細m锛堢閾碉級= 84g*50%=42g m(H2O)=84g*50%=42g 楗卞拰鏃剁閾电殑璐ㄩ噺鍒嗘暟=175g/(100g+175g) =7/11 H2O鐨勮川閲忓垎鏁= 4/11 鍔犲叆纭濋摰鍚庣殑婧舵恫璐ㄩ噺=42g/ 4/11=115.5g 鍔犲叆鐨勭閾电殑璐ㄩ噺=115.5g * 7/11 - 42g = 73.5g-42g =31.5g 杩欓亾棰樼洰涓昏鏄冨療瀛︾敓鐨勫畧鎭掓濇兂锛屽湪棰樼洰涓紝鍓嶄竴...