【单选题】. As he has been well trained, this young man is ________ to be a teacher.
【单选题】Woman: If the weather is this hot tomorrow, we may as well give up the idea of playing tennis in the afternoon. Man: Oh, I don't think it'll last long. The weather forecast says it will cloud over by ...
A.
Weather forecasts are not reliable.
B.
They'd better change their mind.
C.
The tennis game won't last long.
D.
They shouldn't change their plan.
【简答题】在下列情况下,测定结果是偏高、偏低,还是无影响?并说明其原因。(1) 在pH=4的条件下,用莫尔法测定Cl-;(2) 用佛尔哈德法测定Cl-既没有将AgCl沉淀滤去或加热促其凝聚,有没有加有机溶剂;(3) 同(2)的条件下测定Br-;(4) 用法扬斯法测定Cl-,曙红作指示剂;(5) 用法扬斯法测定I-,曙红作指示剂。
【单选题】下列情况中,可能使分析结果偏低的是( )
A.
以盐酸标准溶液滴定某碱样,滴定管来洗净,滴定时内壁挂水
B.
以H2C204.2H2O为基准物质滴定某标准溶液,草酸失去部分结晶水
【简答题】在下列情况下,测定结果是偏高、偏低,还是无影响?并说明其原因(1)在pH=4的条件下,用莫尔法测定Cl-(2)用佛尔哈德法测定Cl-既没有将AgCl沉淀滤去或加热促其凝聚,有没有加有机溶剂(3)在(2)的条件下测定Br-
【单选题】在下列情况下,测定结果偏低的是
A.
在HCl介质中用K 2 Cr 2 O 7 测定铁
C.
用佛尔哈德法测定Br - ,即没有将沉淀滤去或加热促其凝聚,又没有加有机溶剂
【判断题】No one paid any attention to this odd-looking man who might as well have been invisible. (Para. 2) Meaning: Cliff Young looked strange. His presence at the race drew everyone’s attention.
【单选题】称取一定质量的邻苯二甲酸氢钾基准物,用以标定NaOH溶液的浓度,下列情况中能引起测量结果偏低的是
D.
在称取邻苯二甲酸氢钾时,错将0.6324 g记为0.6424 g
【简答题】Directions: There are three passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should ...