【简答题】某氯化铁样品含有少FeC1 2 杂质。现要测定其中铁元素的质量分数,实验按以下步骤进行: 请根据上图流程,回答以下问题: (1)操作Ⅰ所用到的玻璃仪器除烧杯、玻璃棒外,还必须有 、 (填仪器名称),操作Ⅱ必须用到的仪器是 (填编号)。 A.50mL烧杯 B.50mL量筒 C.100mL量筒 D.25mL酸式滴定管 (2)①的X可选用(填化学式),其目的是 。加入氨水要过量的原因是 。 (3)检验沉...
【单选题】(Para 5) Speaking, reading, and writing should be weighted ______ in the assessment.
【单选题】下列境外上市地点中,不属于中国企业境外上市集中地的是()。
【简答题】Direction: Read the following passage. Fill in the numbered blanks by using the information from the passage. Write NO MORE THAN THREE WORDS for each answer. We know that in many cases things aren’t p...
【单选题】What is the direction of vector E?
A.
direction of force exerting on a charge
B.
direction of force exerting on a positive charge
C.
direction of force exerting on a negative charge
【单选题】By saying that nature 'has its own way of purifying water'(Line 5, Para. 3)the author is referring to______.