【单选题】
称取W(g)基准NaCl,溶解后移入250ml容量瓶中,稀释至刻度配成标准溶液,用移液管吸取其分量来标定AgNO3溶液的浓度,在下述情况下何种将使所标AgNO3的溶液的浓度偏低?___
A. 所用砝码的总校正值的负值
B. 移液管的校正值为正值
C. 容量瓶的校正值的正值
D. 滴定管在所用容积区间的校正值为负值
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答案
D
解析
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相关试题
【单选题】
用基准硼砂标定HCl时,操作步骤要求加水50mL,但实际上多加了20mL,这将对HCl浓度产生什么影响?___
A. 偏高
B. 偏低
C. 无影响
D. 无法确定
【单选题】
液-液萃取过程的本质是什么?___
A. 将物质由亲水性转为疏水性
B. 将水合离子改为配合物
C. 将物质由疏水性转为亲水性
D. 将沉淀在有机相中转化为可溶性物质
【单选题】
若要使吸光度降低为原来的一半,最方便的做法是___
A. 将待测液稀释一倍
B. 选用新的测定波长
C. 选用原厚度1/2的比色皿
D. 更换显色剂
【单选题】
用基准物质Na2C2O4标定KMnO4时,下列哪种操作时错误的?___
A. 锥形瓶用Na2C2O4溶液润洗
B. 滴定管用KMnO4标液润洗
C. KMnO4标液盛放在棕色瓶中
D. KMnO4标准溶液放置一周后标定
【单选题】
实验室中常用的干燥剂变色硅胶失效后呈何种颜色?___
A. 蓝色
B. 黄色
C. 红色
D. 绿色
【单选题】
可用哪种方法减少分析测试中的偶然误差?___
A. 对照试验
B. 空白试验
C. 增加平行测试次数
D. 仪器矫正
【单选题】
用基准硼砂标定HCl时,操作步骤要求加水50mL,但实际上多加了20mL,这将对HCl浓度的标定产生什么影响?___
A. 偏高
B. 偏低
C. 无影响
D. 无法确定
【单选题】
(1+1)HCl溶液的物质的量浓度为多少?___
A. 2mol/L
B. 4mol/L
C. 6mol/L
D. 8mol/
【单选题】
常量滴定管可估计到±0.01mL,若要求滴定的相对误差小于0.1%,在滴定时,耗用体积一般控制在:___
A. 10~20Ml
B. 20~30mL
C. 30~40mL
D. 40~50mL
【单选题】
定量分析中,基准物质是___
A. 纯物质
B. 标准参考物质
C. 组成恒定的物质
D. 组成一定、纯度高、性质稳定且摩尔质量较大的物质
【单选题】
测定复方氢氧化铝药片中Al3+、Mg2+混合液时,EDTA滴定Al3+含量时,为了消除Mg2+干扰,最简便的方法是:___
A. 沉淀分离法
B. 控制酸度法
C. 配位掩蔽法
D. 溶剂萃取法
【单选题】
滴定操作中,对实验结果无影响的是:___
A. 滴定管用纯净水洗净后装入标准液滴定
B. 滴定中活塞漏水;
C. 滴定中往锥形瓶中加少量蒸馏水
D. 滴定管下端气泡未赶尽
【单选题】
下列器皿不能直接用酒精灯加热的是:___
A. 试剂瓶
B. 蒸发皿
C. 烧杯
D. 烧瓶
【单选题】
下列仪器在量取或配制标准溶液前不需要润洗的是:___
A. 吸量管
B. 移液管
C. 滴定管
D. 容量瓶
【单选题】
鉴定Ni2+的试剂通常是下列中的哪一种?___
A. 丁二酮肟
B. 硝基苯偶氮间苯二酚
C. 二苯基联苯胺
D. 硫脲
【单选题】
用邻苯二甲酸氢钾标定NaOH溶液浓度时,会造成系统误差的是___
A. 用甲基橙作指示剂
B. NaOH溶液吸收了空气中CO2
C. 每份邻苯二甲酸氢钾质量不同
D. 每份加入的指示剂量不同
【单选题】
有效数字位数是四位的数值是:___
A. 0.0002
B. 0.1000
C. 0.700×102
D. pH=12.80
【单选题】
某同学用硼砂标定标准溶液实验中,溶解硼砂时,用玻棒去搅拌锥形瓶中溶液后,不经处理拿出瓶外,标定结果会:___
A. 偏高
B. 偏低
C. 不一定
D. 无影响
【单选题】
阴离子分离鉴定实验中,Br2在CCl4层显示什么颜色?___
A. 橙色
B. 紫红色
C. 蓝色
D. 黄色
【单选题】
标定NaOH溶液的常用基准物质:___
A. 无水碳酸钠
B. 邻苯二甲酸氢钾
C. 硼砂
D. CaCO3
【单选题】
用K2Cr2O7基准物质配制0.01667mol·L-1溶液一升,下列操作中合适的___
A. 在分析天平上用差减法准确称取K2Cr2O74.903克;
B. 以直接称量法用称量纸在分析天平上称取4.903克;
C. 用600ml烧杯以直接称量法在台天平上称得4.9克;
D. 以直接称量法用称量纸在台天平上称取4.9克
【单选题】
一种钠盐可溶于水,该盐溶液加入HCl溶液后,有刺激性气体产生,同时有黄色沉淀生成,该盐是:___
A. Na2S
B. Na2CO3
C. Na2SO3
D. Na2S2O3
【单选题】
将BaSO4与PbSO4分离开,宜采用:___
A. NH3·H2O
B. HCl
C. H2S
D. NH4AC
【单选题】
可用哪种方法减少分析测试中的偶然误差?___
A. 对照试验
B. 空白试验
C. 增加平行测试次数
D. 仪器矫正
E. 分析结果矫正
【单选题】
称取W(g)基准NaCl,溶解后移入250ml容量瓶中,稀释至刻度配成标准溶液,用移液管吸取其分量来标定AgNO3溶液的浓度,在下述情况下何种将使所标AgNO3的溶液的浓度偏低?___
A. 所用砝码的总校正值的负值
B. 移液管的校正值为正值
C. 容量瓶的校正值的正值
D. 滴定管在所用容积区间的校正值为负值
【单选题】
某工厂排放污水中含有Cr6+离子,其含量仅为10~100μg/g,要求测定误差为2%,可选用下列何种方法测定?___
A. 硫酸亚铁铵滴定法
B. 二苯胺基脲比色法
C. EDTA滴定法
D. H2O2还原EDTA滴定法
【单选题】
用基准硼砂标定HCl时,操作步骤要求加水50mL,但实际上多加了20mL,这将对HCl浓度产生什么影响?___
A. 偏高
B. 偏低
C. 无影响
D. 无法确定
【单选题】
区分晶体与非晶体常用方法是:___
A. 差热分析法
B. 分光光度计
C. X-射线衍射法
D. 色谱法
【单选题】
旋转蒸发仪主要是用于:___
A. 搅拌反应物,使反应加速进行
B. 旋转仪器使反应顺利进行
C. 蒸发并得到产物
D. 蒸发溶剂和浓缩溶液
【单选题】
柱层析时,单一溶剂往往不能取得良好的分离效果,展开剂往往是极性溶剂与非极性溶剂的混合物。下列常见溶剂的极性顺序正确的是:___
A. 石油醚>甲苯>氯仿>丙酮
B. 甲苯>石油醚>氯仿>丙酮
C. 石油醚>丙酮>氯仿>甲苯
D. 丙酮>氯仿>甲苯>石油醚
【单选题】
莫尔法测定Cl-的含量时,要求介质为中性或弱碱性,若溶剂酸度过高,则:___
A. AgCl沉淀不完全
B. AgCl沉淀易胶溶
C. Ag2CrO4沉淀不易生成
D. AgCl沉淀吸附Cl-增强
【单选题】
AgNO3水溶液是:___
A. 酸性
B. 中性
C. 碱性
D. 无法确定酸碱性
【单选题】
称取W(g)基准NaCl,溶解后移入250ml容量瓶中,稀释至刻度配成标准溶液,用移液管吸取其分量来标定AgNO3溶液的浓度,在下述情况下何种将使所标AgNO3的溶液的浓度偏低?___
A. 所用砝码的总校正值的负值
B. 移液管的校正值为正值
C. 容量瓶的校正值的正值
D. 滴定管在所用容积区间的校正值为负值
【单选题】
用基准硼砂标定HCl时,操作步骤要求加水50mL,但实际上多加了20mL,这将对HCl浓度产生什么影响?___
A. 偏高
B. 偏低
C. 无影响
D. 无法确定
【单选题】
液-液萃取过程的本质是什么?___
A. 将物质由亲水性转为疏水性
B. 将水合离子改为配合物
C. 将物质由疏水性转为亲水性
D. 将沉淀在有机相中转化为可溶性物质
【单选题】
物质溶液的颜色是由于选择性地吸收了白光中的某些波长的光所致,硫酸铜呈现蓝色是由于它吸收了白光中的哪种光波?___
A. 蓝色
B. 绿色
C. 黄色
D. 紫色
【单选题】
欲测定离子(或分子)未成对电子数,宜采用下列哪种设备___
A. 磁力天平
B. 电位计
C. 电导仪
D. 红外光谱仪
【多选题】
下列情况中,哪些情况能使测定结果产生正误差?
A. 碘量法测定铜含量,铜样中含有Fe2+
B. 用AgNO3标准溶液于PH为6.5~10.5时,测定NH4Cl的含量
C. 以BaSO4重量法测定Ba2+时,有少量的Fe2+共沉淀产生
D. 某试样在称重时吸潮了
【多选题】
用NaOH滴定硼酸,须在硼酸溶液中加入大量:___
A. 乙醇
B. 丙三醇
C. 甘露醇
D. 水
【多选题】
实验室安全知识:因电器失火,应用下列哪种灭火器?___
A. 泡沫灭火器
B. CO2灭火器
C. 干粉灭火器
D. CCl4灭火器
推荐试题
【单选题】
Which of the following statements is Not True? ___
A. Your boss may be willing to change his behavior than your think.
B. Some managers don’t care how much their words or actions upset staffers.
C. You should tell your managers how their outbursts make you feel.
D. If the boss values your work, he may stop his abusiveness.
【单选题】
Which of the following public places is NOT mentioned that have banned mobiles? ___
A. restaurants
B. gas stations
C. theatres
D. museums
【单选题】
What happened when the cellphone of the speaker’s friend rang? ___
A. His friend answered the phone and the speaker became invisible to his friend.
B. They answered the phone together.
C. The speaker threw away his friend’s cellphone.
D. His friend hung up the phone and kept talking to the speaker. (C)
【单选题】
What happened to the man? ___
A. He had a car accident.
B. He had his arms broken.
C. He lost his mobile phone.
D. He was not able to use his mobile because he was in a remote area.
【单选题】
Which of the following is NOT true? ___
A. Today there are about 400 million cellphone owners.
B. Today there are about 300 million Personal Computer subscribers.
C. Cellphones will be more often used.
D. Cellphones will completely replace Personal Computers.
【单选题】
Which of the following is true? ___
A. Ellen Johnson-Sirleaf stayed in her country during the nation’s civil war.
B. She is still working for the United Nations.
C. She is the first woman ever elected president of an Asian country.
D. She is a Liberia.
【单选题】
What do you know about the solar eclipse? ___
A. Only hundreds of people gazed at it.
B. It was caused by the earth passing in front of the moon.
C. It was not often seen.
D. It started in Mongolia and ended in Brazil.
【单选题】
What is true about this meeting between the USA and China? ___
A. It was a meeting between Xi Jinping and Donald Trump.
B. It was the first time that the Chinese president had visited the United States.
C. The issue of the Olympics was discussed.
D. South Korea’s nuclear weapons program was discussed.
【单选题】
In which year did the station’s first permanent crew arrived? ___
A. 1998
B. 2000
C. 2002
D. 2003
【单选题】
If elected, ________________. ___
A. Richardson would be the first Hispanic President.
B. Clinton would be the first African-American President.
C. Romney world be the first Hispanic President.
D. Clinton would be the first Mormon President.
【单选题】
What are the things that the speaker’s inner and outer life based on? ___
A. Money
B. Health
C.
D. elicious food
【单选题】
What kind of things has its own reason for existing? ___
A. Questioning
B. The structure of reality
C. Curiosity
D. The mysteries of eternity
【单选题】
Who are so full of doubts? ___
A. Fools and fanatics
B. Wise people
C. Professors
D. University students
【单选题】
To the speaker, what kind of things always win in life? ___
A. Truth and love
B. Power and status
C. Great minds
D. Money and material
【单选题】
What’s the key word of the speaker? ___
A. Love
B. Power
C. Freedom
D. Curiosity
【单选题】
What happened to the man? ___
A. He committed identity theft.
B. He was put in prison.
C. He reported a case of theft to police.
D. He robbed a bank.
【单选题】
What is the attitude of Mrs. Washington? ___
A. She tries to cover up for little George.
B. She thinks Mr. Washington should not ask George directly.
C. She encourages George to chop down the tree.
D. She thinks Mr. Washington should put the blame on the sharp axe.
【单选题】
What do Nancy’s colleagues think about her transgender transition? ___
A. They think it is ridiculous.
B. They make a big fuss about it.
C. They take it lightly.
D. They are sympathetic.
【单选题】
What are the two women talking about? ___
A. They are talking women’s liberation.
B. They are talking about an ideal husband.
C. They want a rewarding job.
D. They are talking about women’s choice between family and career.
【单选题】
According to what you’ve heard, which of the following is NOT true? ___
A. The two ten-minute workouts help people get into shape in a short time.
B. The two ten-minute workouts are designed for the people of certain level of fitness.
C. The two ten-minute workouts help people to lose weight and to be vigorous.
D. The two ten-minute workouts are suitable for most people.
【单选题】
What does Cindy say about visiting Costa Rica in June? ___
A. It is bad because June falls in the rainy season.
B. It is bad because there is almost no sunshine in June.
C. It is not bad because it seldom rains on the coast.
D. It is not bad because it does not rain all the time and in all the places.
【单选题】
What did the professor say about the translation of idioms across language? ___
A. Almost all idioms are translatable and can be universally used.
B. Idioms are hardly translatable and cannot be universally used.
C. Not all idioms are translatable but many have translations in other language.
D. All idioms are translatable and tend to become international.
【单选题】
According to Professor Randal, which of the following is true for SAT II? ___
A. It tests your critical thinking and problem-solving skills.
B. It is more content oriented.
C. It is designed to measure subject-area knowledge.
D. It is designed to measure achievement in
E. nglish, math, reading, and science.
【单选题】
The movie in IMAX format adds the amazing effects except ___________. ___
A. the effect of sound
B. the effect of view
C. the effect of landscape
D. the effect of mystery
【单选题】
What can we learn from the conversation? ___
A. Nobody thinks he is under stress.
B. People should avoid stress completely.
C. Stress is a normal state of affairs.
D. Nobody is subject to stress.
【单选题】
What is Tom’s attitude towards the mobile phone? ___
A. It is very convenient to send text messages.
B. People have to put up with the inconvenience of using mobile phones.
C. He feels important when he uses his mobile phone in public.
D. He cannot live a day without his mobile phone.
【单选题】
Where did Helena start learning Dutch? ___
A. Spain
B. Holland
C. Sri Lanka
D. Indonesia
【单选题】
According to what the broadcaster says about what happened when the blackout occurred, which of the following is not true? ___
A. People crowded the streets of New York.
B. Throngs of people walked across the bridge, screaming and cursing.
C. The blackout stopped subways, buses and turned off traffic lights.
D. Many people are thinking of hitching a ride.
【单选题】
Who is Dr. Burkey? ___
A. The anchor
B. The questioner
C. A student
D. A clinical psychologist.
【单选题】
Which is true about Gandhi’s nonviolence? ___
A. There will be no pains and defeats when people use nonviolence.
B. People should be prepared to die like a soldier when they use nonviolence.
C. Nonviolence means that you have to accept injustice.
D. Soldiers can use violence against violence.
【单选题】
肖东和外祖父是___
A. 直系血亲
B. 直系姻亲
C. 旁系血亲
D. 旁系姻亲
【单选题】
按罗马法的亲等算法,小杨和叔叔的孙子是___
A. 三等亲
B. 四等亲
C. 五等亲
D. 六等亲
【单选题】
甲(男)的外祖母乙是丙(女)的父亲丁的胞姊,因此___
A. 乙是丙的姑母,丁是甲母的舅父
B. 乙是丙的姨母,丙是乙的甥女
C. 乙是丙的舅母,丁是甲母的叔父
D. 乙是丙的婶母,丙是乙的侄女
【单选题】
下列各种亲属关系中,属于直系拟制血亲的有___
A. 外祖父母与外孙子女
B. 养父母与养子女
C. 祖父母与孙子女
D. 继父母与未受其抚养教育的继子女
【单选题】
被告人王某,男,48岁,某村农民。被告人马某,女,45岁,某村农民,系被告人王某之妻。被告人王某与其兄二人按月轮流负担其母(67岁,丧失劳动能力)的生活费。2003月份,被告人王某以收入不足等理由,向其兄提出要求,要其兄独自负担母亲的生活费一年。在向其兄说过此事后,未经其兄、母的同意,被告人王某便拒不负担赡养义务。8月23日早上,其母轮到被告人王某家吃饭,途中与被告人马某相遇,马某便对婆婆进行辱骂,不准其进屋,并将老人推倒在地,8月25日晚上,其母到王某家,见儿子和几个孩子正在吃饭,便哀求儿子给点饭吃。王某未予理睬,老人便自盛了一碗饭,正吃时,马某从外面回来,见状便恶语相加,并冲上去把碗抢下来,随后又将老人打了一顿,赶出门外,8月27日,老人忍无可忍,当众诉冤。之后因生活无着,被迫含愤服毒而死。问:构成虐待罪还是遗弃罪?___
A. 虐待罪
B. 遗弃罪
【单选题】
甲男与乙女通过网聊恋爱,后乙提出分手遭甲威胁,乙无奈遂于甲办理了结婚登记。婚后甲得知,乙婚前就患有医学上不应当结婚的疾病且久治不愈,于是甲向法院起诉撤销该婚姻,下列说法正确的是___
A. 法院应判决撤销该婚姻
B. 该案应判决宣告该婚姻无效
C. 对该案的审理应当进行调解
D. 当时人可以对法院的处理结果依法提出上诉
【单选题】
甲男与乙女系出自同一外祖父母的表兄妹,后来乙女被他人收养。根据我国婚姻法的规定,他们___
A. 可以结婚
B. 如果双方不生育子女可以结婚
C. 不能结婚
D. 以上均不正确
【单选题】
某甲与某乙已登记结婚,但未同居,也未举行婚礼。之后某甲后悔与某乙结婚,进行下列( )行为后,婚姻关系才能解除。___
A. 调解
B. 宣布婚姻无效
C. 离婚
D. 撤销结婚登记
【单选题】
甲乙夫妻经协商同意离婚,甲因出差委托丙去离婚登记机关代为办理离婚登记手续,依我国法律,丙___
A. 可以代理
B. 在甲乙双方同意下可以代理
C. 在取得甲授权委托书的情况下可以代理
D. 不能代理
【单选题】
甲乙结婚后购得房屋一套,仅以甲的名字进行了登记。后甲乙感情不和,甲擅自将房屋以时价出售给不知情的丙,并办理了房屋所有权变更登记手续,下列正确的是___
A. 买卖合同有效,房屋所有权未转移
B. 买卖合同无效,房屋所有权已转移
C. 买卖合同有效,房屋所有权已转移
D. 买卖合同无效,房屋所有权未转移