题干

如图所示,把试管放入盛有25℃澄清饱和石灰水的烧杯中,试管中开始放入几块镁条,再用滴管滴入5mL的盐酸于试管中.试回答下列问题:(提示:Ca(OH)2溶解度随着温度的升高而减小)

(1)实验中观察到的现象有____ 

(2)产生上述实验现象的原因是____ 

(3)写出有关的离子反应方程式____ 

(4)由实验可知,MgCl2和H2的总能量____ (填“大于”、“小于”或“等于”)镁条和盐酸的总能量.

(5)如将本题中“25℃澄清饱和石灰水”换成“20℃的碳酸饮料”进行探究实验,实验中观察到的另一现象是____ 其原因是____ 

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答案(点此获取答案解析)

\u9541\u6761\u4e0a\u6709\u6c14\u6ce1\u4ea7\u751f\uff0c\u9541\u6761\u9010\u6e10\u6eb6\u89e3\uff0c\u77f3\u7070\u6c34\u53d8\u6d51\u6d4a,Mg+2HCl=MgCl2+H2\u2191\u8be5\u53cd\u5e94\u662f\u653e\u70ed\u53cd\u5e94\uff0c\u4f53\u7cfb\u6e29

同类题4

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    I was in my first year of college, making friends and enjoying life, but then my whole world turned upside down. I had a heart attack. It felt like someone was stabbing (刺) me in the chest with a knife over and over again.

    After three months of rest I went back to college, but then things took a turn for the worse. I was staying at my Nana's house and woke up in the middle of the night with a terrible pain in my chest. I knew I was having a heart attack again.

    I couldn't even shout for help. Luckily my grandpa was going to the toilet and heard me falling out of bed. If it wasn't for him, I probably wouldn't be here.

    The two holes in my heart were causing the problems and I needed an operation immediately to repair them. Unfortunately, the surgery didn't go well and they only managed to repair one of the holes.

    When I woke up from the operation, I had a really dry mouth and couldn't wait to have something to eat and drink. The biggest shock of all came when I was told that I needed a heart transplant and was put on the register. The doctors were stunned at how quickly heart failure came on – it usually takes years, but it took my heart less than six months to get to that stage. My whole world came crashing down, but I stayed strong. It was a choice between crying every day and getting on with my life.

    As time went on, life became even harder. I hated feeling weak all the time and needing help with everything. It got to the point where I thought I would never get a new heart. I was diagnosed with depression.

    Even though I thought that Christmas 2008 would be my last, I really enjoyed it and even had a good New Year. Everyone was crying for me when the clock struck midnight and they told me to keep fighting.

    A week later, I got a call from the doctors saying they'd found a suitable donor (捐赠人). My wish came true and thankfully the operation went well. I spent four hours in surgery where they took out my old heart and put a new one in. When I woke up I burst out crying. I had a second chance at life.