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【简答题】
某种粗盐中含有泥沙、Ca 2 ＋ 、Mg 2 ＋ 、Fe 3 ＋ 、SO等杂质。某同学在实验室中设计了用这种粗盐制备精盐的方案如下(用于沉淀的试剂稍过量)： 请回答以下问题： (1)为操作Ⅳ选择所需仪器(用标号字母填写)：________。 A．烧杯 B．试管 C．玻璃棒 D．分液漏斗 E．漏斗 F．酒精灯 G．蒸发皿 (2)操作Ⅲ中常用Na 2 CO 3 溶液、NaOH溶液、BaCl 2 溶液作为除杂试剂，则加入除杂试剂的顺序为：NaOH溶液→________→________。 (3)操作Ⅲ中，判断加入BaCl 2 已过量的方法是___________________________________ (4)操作Ⅴ应选择的酸是________，若将操作Ⅴ与操作Ⅳ的先后顺序对调，将会对实验结果产生的影响是___________________________________ (5)操作Ⅵ是________(选择合理操作的名称，用标号字母按操作先后顺序填写)。 a．过滤、洗涤 B．蒸发、浓缩 c．萃取、分液 D．冷却、结晶
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皮皮学刷刷变学霸
举一反三
【单选题】(1~2题共用题干)新生儿女,出生后3天。皮肤.巩膜出现黄染,精神.食欲尚好,大便黄色糊状,查血清胆红素浓度1428μmol/L,血常规无异常,小儿血型为O型,其母为A型。该患儿最可能是
A.
溶血性黄疸
B.
阻塞性黄疸
C.
先天性黄疸
D.
生理性黄疸
E.
肝细胞性黄疸
【单选题】Lightning strikes during summer thunderstorms are the most dangerous weather condition faced by those engaged in activvities.
A.
indoor
B.
outdoor
C.
indoors
D.
outdoors
【简答题】何为延髓背外侧综合征
【单选题】It is often said that lightning never strikes twice in the same place. But this is not rue. Go ask the forest rangers(护林员). Rangers who spend their summers as fire fighters will tell you that every th...
A.
It is often said that lightning never strikes twice in the same place.
B.
Rangers who spend their summers as fire fighters will tell you that every thunderstorm brings several bolts of lightning to their craggy lookout station.
C.
Not only can lightning strike twice in the same place, but it is likely to.
D.
The familiar saying actually states the opposite of what really happens during an electrical storm.
【单选题】对恶性肿瘤的描述不正确的是()。
A.
可发生在任何年龄,任何器官的组织
B.
早期发现的恶性肿瘤也都不可能治愈
C.
从组织学上分为上皮性的癌、非上皮性的肉瘤及白血病
D.
特征是体内某些细胞丧失了正常调控,出现无节制的生长和异常分化。
【简答题】( )表面发现裂纹的，该结构件应判为不合格。 A.重要结构件 B.一般结构件 C.结构件 D.齿轮表面
【单选题】Lightning strikes during summer thunderstorms are the most dangerous weather condition faced by those engaged in ________ activities
A.
indoor
B.
outdoor
C.
indoors
D.
outdoors
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