问题 问答题

下列反应中生成物总能量低于反应物总能量的是(  )

A.氢氧化钡晶体和氯化铵晶体混合反应

B.盐酸与金属镁反应

C.石灰石高温煅烧

D.水的分解

答案

反应中生成物总能量高于反应物总能量,说明该反应是一个放热反应.

A、氢氧化钡晶体和氯化铵晶体混合反应是一个吸热反应,故A错误;

B、盐酸与金属镁反应是放热反应,故B正确;

C、石灰石高温煅烧是一个吸热过程,故C错误;

D、水的分解是吸热的,故D错误.

故选B.

单项选择题
完形填空

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