【简答题】某烧碱溶液中含有少量杂质(不与盐酸反应),现用中和滴定测定其浓度。 (1)滴定:①用 式滴定管盛装c mol/L盐酸标准液。如图表示某次滴定时50 mL滴定管中前后液面的位置。请将用去的标准盐酸的体积填入③表空格中,此时滴定管中液体的体积 mL。 ②下表是4种常见指示剂的变色范围: 指示剂 石蕊 甲基橙 甲基红 酚酞 变色范围(pH) 5.0—8.0 3.1—4.4 4.4—6.2 8.2—10....
【单选题】The paradox is that every day we get two sets of messages at odds with each other.
A.
The contradiction is that every day we get two sets of messages disagreeing with each other.
B.
The contradiction is that every day we get two sets of strange and unusual messages.
C.
The condition is that every day we get two sets of messages echoing each other.
【单选题】We may infer that the fastest way for the computer to send messages to others is by using ______.
【判断题】[1414]()长期进款由于借款期限长.风险大.因此借款成本也较高。
【单选题】The paradox is that every day we get two sets of messages at odds with each other.
A.
The contradiction is that every day we get two sets of messages disagreeing with each other.
B.
The contradiction is that every day we get two sets of strange and unusual messages.
C.
The condition is that every day we get two sets of messages echo each other.
【单选题】发电机调节器是通过调整下列哪项来调整发电机电压的?
【简答题】以下零件是用 材料制成?请解释其材料的牌号含义:该材料平均含 量(中文表元素名称)为 % 。
【单选题】下列有关实验的描述正确的是
A.
用湿润的pH试纸测定溶液的pH,测定结果偏小,该溶液一定呈酸性
B.
中和滴定实验中,锥形瓶用蒸馏水洗净后即可使用,滴定管用蒸馏水洗净后,须干燥 或用待装液润洗后方可使用
C.
将碘水倒入分液漏斗,加入适量乙醇,振荡后静置,能将碘萃取到乙醇中
D.
向含有FeCl 2 杂质的FeCl 3 溶液中通入足量C1 2 后,充分加热蒸干,可得到纯净的FeCl 3 固体