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【简答题】
已知某NaOH试样中含有NaCl杂质，为测定试样中NaOH的质量分数，进行如下步骤实验： ①称量1.00 g样品溶于水，配成250 mL溶液； ②准确量取25．00 mL所配溶液于锥形瓶中； ③滴加几滴酚酞溶液； ④用0.10 mol/L的标准盐酸滴定三次，每次消耗盐酸的体积记录如下 请回答： (1)用______滴定管(填“酸式”或“碱式”)盛装0．10 mol/L的盐酸标准液 (2)滴定到终点时溶液由______色变成______色。 (3)烧碱样品的纯度为_______________。 (4)若出现下列情况，测定结果偏高的是______。 a．滴定前用蒸馏水冲洗锥形瓶 b．在振荡锥形瓶时不慎将瓶内溶液溅出 c．若在滴定过程中不慎将数滴酸液滴在锥形瓶外
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举一反三
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孕妇年龄32岁
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妊娠合并羊水过多
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产前检查发现为臀位
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早孕期间有过感冒发热史
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检查发现子宫大小与孕周不符
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【单选题】According to the passage, which of the following adjectives best describes those people who work in large cities and live in villages?
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Original.
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Quiet.
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Arrogant.
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Insensitive.
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高龄
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【单选题】According to the passage, which of the following statements is true?
A.
Tackling a player who is not carrying the hall is a ten-yard penalty.
B.
It is legal to pass the ball in rugby it' you are already down.
C.
Only the offensive team in rugby can be called 'ruggers'.
D.
All of the above.
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初孕妇，年龄＜18岁
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糖尿病
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既往有慢性肾炎病史
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【单选题】According to this passage, optimum population ______.
A.
refers to the population size at which the average level of welfare will be as high as possible
B.
refers to the population size at which the total amount of welfare will be as great as possible
C.
is a difficult philosophical issue which remains to be resolved in the future
D.
is a difficult philosophical issue which Derek Parfit has successfully settled in Reasons and Persons
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【单选题】According to the WH0，there are now 10 million AIDS patients in the world．
A.
Right
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【单选题】Temperatures in the United States ______ measured according to the Fahrenheit Scale, on which 32 degrees ______ the freezing point and 212 degrees the boiling point.
A.
are is
B.
are are
C.
is is
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is are
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【单选题】According to the WH0，there are now l o million AIDS patients in the world．
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Right
B.
Wrong
C.
Not mentioned
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【单选题】下列哪项不属于妊娠中的高危因素( )
A.
孕妇年龄32岁
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【单选题】According to the passage, which of the following adjectives best describes those people who work in large cities and live in villages?
A.
Original.
B.
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C.
Arrogant.
D.
Insensitive.
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【单选题】下列哪项不属于VTE危险因素
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高龄
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【简答题】According to a survey, ______ of the children investigated say that parents never check where they've been online.
查看完整题目与答案
【单选题】According to the passage, which of the following statements is true?
A.
Tackling a player who is not carrying the hall is a ten-yard penalty.
B.
It is legal to pass the ball in rugby it' you are already down.
C.
Only the offensive team in rugby can be called 'ruggers'.
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All of the above.
查看完整题目与答案
【单选题】从病因角度看下列哪项不属于妊娠期高血压疾病的高危因素( )
A.
初孕妇，年龄＜18岁
B.
糖尿病
C.
多胎妊娠
D.
既往有慢性肾炎病史
E.
母儿血型不合
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【单选题】According to this passage, optimum population ______.
A.
refers to the population size at which the average level of welfare will be as high as possible
B.
refers to the population size at which the total amount of welfare will be as great as possible
C.
is a difficult philosophical issue which remains to be resolved in the future
D.
is a difficult philosophical issue which Derek Parfit has successfully settled in Reasons and Persons
查看完整题目与答案
【单选题】According to the WH0，there are now 10 million AIDS patients in the world．
A.
Right
B.
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【单选题】Temperatures in the United States ______ measured according to the Fahrenheit Scale, on which 32 degrees ______ the freezing point and 212 degrees the boiling point.
A.
are is
B.
are are
C.
is is
D.
is are
查看完整题目与答案