【題目】下表是某實(shí)驗(yàn)報(bào)告中的一組數(shù)據(jù)：

實(shí)驗(yàn)

序號(hào)

試劑1

試劑2

混合前

溫度/℃

混合后最高或最低溫度/℃

①

3.2 mL水

3.2 g Na2CO3固體

20

24.3(t1 )

②

35 mL稀鹽酸

3.2 g Na2CO3固體

20

25.1(t2 )

③

35 mL水

2.5 g NaHCO3固體

20

18.5(t3 )

④

35 mL稀鹽酸

2.5 g NaHCO3固體

20

16.2(t4)

（1）從實(shí)驗(yàn)①、③數(shù)據(jù)可知：Na2CO3溶于水________熱量，NaHCO3溶于水________熱量(填“放出”或“吸收”)。

（2）根據(jù)t2>t1 可知Na2CO3與稀鹽酸反應(yīng)______熱量，根據(jù)t4<t3 可知：NaHCO3與稀鹽酸反應(yīng)______熱量(填“放出”或“吸收”)。

【答案】（1）放出 吸收 （2）放出 吸收

【解析】

試題分析：（1）從實(shí)驗(yàn)①、③數(shù)據(jù)可知：Na2CO3溶于水溶液溫度升高，即Na2CO3溶解時(shí)可放出熱量。NaHCO3溶于水溶液溫度降低，即NaHCO3溶解時(shí)可吸收熱量。

（2）根據(jù)t2>t1 可知Na2CO3與稀鹽酸反應(yīng)放出熱量，根據(jù)t4<t3 可知：NaHCO3與稀鹽酸反應(yīng)吸收熱量。

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