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问题 不定项选择题

在1 L密闭容器中，把1mol A和1mol B混合发生如下反应：3A(g)+B(g)xC(g)+2D(g)，当反应达到平衡时，生成0．4mol D，并测得C的平衡浓度为0．4mol·L-1，下列叙述中正确的是[ ]

A．x的值为2

B．A的转化率为40%

C．B的平衡浓度为0.8 mol·L-1

D．D的体积分数为25%

答案

AC

问答题

有一单摆，在地球表面为秒摆，已知月球表面的重力加速度约为地球表面重力加速度的1/6.

（1）将该单摆置于月球表面，其周期多大？

（2）若将摆长缩短为原来的1/2，在月球表面时此摆的周期多大？

（3）该秒摆的摆长多少？（g="9.8" m/s2）
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单项选择题

DOM is a platform- and language- （） API that allows programs and scripts to dynamically access and update the content, structure and style of WWW documents (currently, definitions for HTML and XML documents are part of the specification). The document can be further processed and the results of that processing can be incorporated back into the presented （） . DOM is a （） -based API to documents, which requires the whole document to be represented in （） while processing it. A simpler alternative to DOM is the event-based SAX, which can be used to process very large （） documents that do not fit into the memory available for processing.

DOM is a platform- and language-（） API that allows programs and scripts to dynamically access and update the content

A．specific

B．neutral

C．contained

D．related
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