師1958△H = 0KCI(固)+H2O(液)KCI水溶液WigW2 g(W1 + W2) g终温始温t2,Pt1,P△H1△H2KCI(固)+H2O(液)W1gW2 g终温t2,P
師AH = AH1 + AH21958因为量热计为绝热系统,所以△H=0,则AH1= -△H2H1 = WiC1(t2 - t1) + W2C2(t2 - t1) +K(t2 - t1)式中:C1、C2分别为KCI(固)和水的恒压热容;K为量热计的热容量,即量热计温度升高1℃时所需的热量△H2 = -△H1= WiCi(t2 - t1) + W1Ci(t2 - ti) + K(t2 - t1)如果已知K,测得ti和t2后就可通过上式算出△H2,△H为在压力P、温度t2下,WigKCl(固)溶于W2g水的溶解热,将其换算成1mol的热效应,即为KCI的溶解热