搜题请搜索小程序“爱下问搜题”
问题 选择题

下列化学用语书写正确的是

A．氢气分子的电子式：H∶H

B．硫原子的结构示意图：

C．溴化钠的电子式：

D．苯的分子式：

答案

答案：A

题目分析：A、氢气是含有非极性键的单质，其电子式为H∶H，A正确；B、硫原子的最外层电子数是6个，其原子结构示意图为，B不正确；C、溴化钠是离子化合物，含有离子键，电子式为，C不正确；D、苯的分子式是C6H6，D不正确，答案选A。

单项选择题

在Word编纂状况下，新建一个Word文档的操作是（）。

在Word编纂状况下，新建一个Word文档的操作是（）。

A.单击“起头”菜单中的“轨范”选项下的“MicrosoftWord”

B.单击“文件”菜单中的“打开”

C.选择“文件”菜单中的“新建”选项

D.单击工具栏中的“打开”按钮
查看答案
单项选择题

Current Group, a Germantown-based technology firm, has taken over an ordinary looking house in Bethesda and turned it into a laboratory for smart-grid technology, the system the company believes will bring the nation’s electricity grids into the digital age.
In the front yard stands a utility pole hooked up to a special transformer that connects the power lines to high-speed Internet. Hundreds of sensors attached to the lines monitor how power flows through the home. That information is then sent back to the utility company.
The process lets a utility more efficiently manage the distribution of electricity by allowing two-way communication between consumers and energy suppliers via the broadband network on the power lines. Based on data they receive from hundreds of homes, utilities can monitor usage and adjust output and pricing in response to demand. Consumers can be rewarded with reduced rates by cutting back on consumption during peak periods. And computerized substations can talk to each other so overloaded circuits hand off electricity to those that have not fully loaded, helping to prevent blackouts.
Some utility companies have launched initiatives to give consumers data about their energy consumption habits in an effort to lower energy bills. Smart-grid technology takes such programs further by automating electricity distribution, which would make grids more reliable and efficient.
By partnering with utilities, the company hopes to tap into $4.5 billion in stimulus grants intended to encourage smart-grid development. When he announced the funding, President Obama pointed to a project in Boulder, Colo. , as an example of a successful smart-grid experiment. Current is one of the companies working on the project.
Current’s chief executive Tom Casey believes the technology will help utility companies better distribute electricity produced by renewable resources, such as solar panels or wind farms. " A smart grid’s system can be paired up with the renewable resources so that when the renewable source is varying, the overall load can be varied as well, " Casey told the House Select Committee on Energy Independence and Global Warming. " This will reduce or eliminate the need for backup coal or gas-based power generation plants. \

For smart-grid technology to work, which of the following is a must

A．The front yard of a house with a tall wooden pole.

B．A huge hook that can connect power lines together.

C．High-speed Internet access and Internet services.

D．Many monitors through which power flowing can be seen.
查看答案