盐酸滴入装有氢氧化钠溶液的烧杯中，用温度计测出烧杯中溶液的温_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

盐酸滴入装有氢氧化钠溶液的烧杯中，用温度计测出烧杯中溶液的温度，溶液温度随加入稀盐酸的质量而变化如图所示，下列叙述错误的是

A．从A到B过程中，烧杯中溶液的pH逐渐减小

B．稀盐酸与氢氧化钠溶液发生的反应是放热反应

C．B点表示酸碱恰好完全反应

D．随稀盐酸的加入，反应放出的热量由少变多，再由多变少

答案

答案：D

题目分析：A、从A到B过程中，表示的是盐酸滴入装有氢氧化钠溶液，所以烧杯中溶液的pH逐渐减小，正确，B、根据图象可以看出从A到B过程中，温度不断上升，说明稀盐酸与氢氧化钠溶液发生的反应是放热反应，正确，C、B点温度最高，表示的是酸碱恰好完全反应，正确，，D、随稀盐酸的加入，反应放出的热量由少变多，当反应结束后，随着稀盐酸的加入，相当于冷却降温的作用，所以温度又开始逐渐下降，并不是反应放出的热量由多变少，错误，故选D

完形填空

When I was 16 years old, I made my first visit to Disneyland in America. It wasn’t the first time I had been    36 . Like most English children I learned French 37 school and I had often been to France, so I     38 speaking a foreign language to people who didn’t understand 39 . But 40　I went to America, I was really looking forward to__41_ a nice easy holiday without any 42　problems.
__43__wrong I was! The misunderstanding began   44 the airport. I was looking for a 45__telephone to give my friend Danny a 46 and tell her I had arrived. A   47 old man saw me looking lost and asked   48 __ he could help me.
“Yes.” I said，“I was to give my friend a ring. ”“Well, that’s nice,” he said. “Are you getting   49 ? But aren’t you a bit young?”“ 50 is talking about marriage?” I replied. “I just want to give my friend a ring to tell her I’ve arrived. Can you tell me   51  there’s a phone box?”“Oh!” he said, “there’s phone downstairs.”
When at last we did meet up, Danny explained the misunderstanding to me. “Don’t worry,”she said to me, “I had so many   52 at first. There are lots of words which the Americans   53  differently in meaning from us British. You’ll soon get used to   54 funny things they say. Most of the   55 , British and American people understand each other!”

A．get used to

B．was used to

D．information

B．to be married

B．difficulties

单项选择题

变频调节的原理是改变变频器输出的（）来调节感应电动机的转速。

A.交流电频率

B.交流电电压

C.电动机电流

D.电磁感应值