问题 选择题

小玲同学对所学部分化学知识与生活、生产联系归纳如下,其中有错误的是(  )

A.煤气中毒---主要由一氧化碳引起

B.N2性质稳定---可用于填充食品袋防腐

C.把煤做成蜂窝状---可以使煤燃烧更旺

D.用碱面(纯碱)洗衣物---纯碱溶液呈碱性且化学式为NaHCO3

答案

A、由于煤气中含有有毒气体一氧化碳,而会造成中毒,因此,煤气中毒其实就是一氧化碳中毒;故A正确;

B、利用氮气通常情况下不与其它物质反应的性质,常用氮肥充填食品袋以隔绝食品与氧气的接触,而防止食品较快地腐败;故B正确;

C、把煤做成蜂窝状可使煤与氧气更充分接触,从而使煤燃烧更旺;故C正确;

D、纯碱为碳酸钠的俗称,其化学式为Na2CO3,而化学式为NaHCO3的物质俗称小苏打;故D不正确.

故选D.

单项选择题

阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。学科&网

Hundreds of people have formed impressions of you through that little device(装置) on your desk. And they’ve never actually   41   you. Everything they know about you   42   through this device, sometimes from hundreds of miles away.   43   they feel they can know you   44   from the sound of your voice. That’s how powerful the   45   is.

Powerful, yes, but not always   46  . For years I dealt with my travel agent only by phone. Rani, my faceless agent whom I’d never met   47  , got me rock-bottom prices on airfares, cars, and hotels. But her cold voice really   48   me. I sometimes wished to   49   another agent.

One morning, I had to   50   an immediate flight home for a family emergency. I ran into Rani’s office   51  . The woman sitting at the desk,   52   my madness, sympathetically jumped up. She gave me a   53   smile, nodded while listening patiently, and then printed out the   54   immediately. “What a wonderful lady!” I thought.

Rushing out   55   I called out over my shoulder, “By the way, what’s your name?” “I’m Rani,” she said. I turned around and saw a   56   woman with a big smile on her face waving to wish me a safe trip. I was   57  ! Why had I thought she was cold? Rani was, well, so   58  .

Sitting back in the car on the way to the airport, I figured it all out. Rani’s   59  ---her warm smile, her nods, her ‘I’m here for you’   60  ---were all silent signals that didn’t travel through wires.

48()

A. annoyed

B. interested

C. discouraged

D. confused