题干

某化学兴趣小组为探究“氢氧化钠溶液与盐酸发生中和反应时溶液温度的变化情况”,进行了如下实验:

实验一:配置质量分数为10%的氢氧化钠溶液50g.

(1)计算,需称取氢氧化钠的质量为____ g.

(2)配置该溶液所需要的仪器有:烧杯、量筒、胶头滴管和____ (写仪器名称).

实验二:在一定体积的10%的氢氧化钠溶液中滴加10%的盐酸(室温下),反应中溶液温度的变化如下:

(1)该反应的化学方程式为____ .

(2)表中△t1的值为____ .

(3)试绘出溶液温度变化与加入盐酸体积之间的关系图____ .

(4)根据所绘曲线分析,加入盐酸的体积在0~10mL时,溶液温度变化的趋势及其原因是____ .

(5)其他条件不变,若改用20%的盐酸进行滴加,结合对上述曲线的分析,大胆猜想新曲线最高点的位置(不考虑溶液密度和比热容的变化及热量散失等影响因素).

①横坐标及猜想理由:____ ;

②纵坐标及猜想理由:____  .

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答案(点此获取答案解析)

5,\u73bb\u7483\u68d2,NaOH+HCl=NaCl+H2O,0,,\u968f\u7740\u4e2d\u548c\u53cd\u5e94\u7684\u8fdb\u884c\uff0c\u7531\u4e8e\u53cd\u5e94\u653e\u70ed\uff0c\u6eb6\u6db2\u6e29\u5ea6\u4e0a\u5347,5\uff0c\u5f53\u6070\u597d\u5b8c\u5168\u53cd\u5e9

同类题4

阅读下列短文,从每题所给的A、B、C和D项中,选出最佳选项。

Guilin is my favorite city in China because of its beauty, its waterways, its cafes, and most of all because I met my wife there. It is her hometown and we will both retire there in a few years.

Not only is Guilin a fascinating city, there are many interesting places to visit within a short drive from there. The Ling (sometimes called Lingqu) canal is the oldest canal in the world. It was built about 2,200 years ago and connects two major river systems, the Yangtze (to the east) and the Pearl River.

Longsheng Rice Terraces (龙胜梯田) is another manmade wonder that was built around 650 years ago. I have some photos of both of these places in my China Daily homepage Albums. Gudong Waterfall Park(古东瀑布) is another attraction that is worth visiting. The hike to the top of all these waterfalls isn’t very difficult and if you want, you can take a ride to the bottom on a personal rail car whose speed you can control with a brake.

If you want you can also climb up some of the waterfalls with the help of chains that are placed for the convenience of amateur climbers.

I have only been in Guilin during the winter and spring but my wife tells me it gets pretty hot in the summertime. That’s OK because I grew up in the Midwest of the US where it gets very hot and humid during the summer months. It rarely freezes in the winter and the spring and autumn are pleasant. Guilin receives a lot of rain, especially in late spring and early summer. Because of this there is lush(多汁的) plant life and many large trees in the area. 

Being from California I’m used to having a car to get around. In fact, it’s practically a necessity in California. But in Guilin almost everything is within walking distance and if you need to go further, public buses are available every five minutes on the busy streets and every 10-15 minutes just about everywhere else. There are plenty of taxis too and most trips are only six yuan.

It’s a perfect place to retire.