(8分)实验室利用如图装置进行中和热的测定。回答下列问题:⑴

(8分)实验室利用如图装置进行中和热的测定。回答下列问题:

⑴该图中有两处实验用品未画出,它们是________________、____________________;

⑵在操作正确的前提下提高中和热测定的准确性的关键是:_________________________

⑶如果用0.5mol/L的盐酸和氢氧化钠固体进行实验,则实验中所测出的“中和热”将________ (填“偏大”、“偏小”、“不变”)原因是______________________________________

 

答案

(共10分)

 ⑴环形玻璃搅拌棒(2分)   烧杯上方的泡沫塑料盖或硬纸板(2分);   

⑵提高装置的保温效果或尽量减少热量损失;(2分)   

⑶偏大 (2分)      固体NaOH溶于水放热(2分)

解析:

 

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