题目内容
已知下列热化学方程式:
(1)CH3COOH(l)+2O2(g) ="==" 2CO2(g)+2H2O(l) △H1= -870.3 kJ·mol-1
(2)C(s)+O2(g) ="==" CO2(g) △H2= -393.5 kJ·mol-1
(3)H2(g)+O2(g) ="== " H2O(l) △H3= -285.8 kJ·mol-1
则反应2C(s)+2H2(g)+O2(g)===CH3COOH(l) 的焓变△H为( )kJ·mol-1
(1)CH3COOH(l)+2O2(g) ="==" 2CO2(g)+2H2O(l) △H1= -870.3 kJ·mol-1
(2)C(s)+O2(g) ="==" CO2(g) △H2= -393.5 kJ·mol-1
(3)H2(g)+O2(g) ="== " H2O(l) △H3= -285.8 kJ·mol-1
则反应2C(s)+2H2(g)+O2(g)===CH3COOH(l) 的焓变△H为( )kJ·mol-1
A.488.3 | B.-244.15 | C.244.15 | D.-488.3 |
?D
(2)×2 +(3)×2-(1)得2C(s)+2H2(g)+O2(g)===CH3COOH(l)
2△H2+2△H3 —△H1=(-393.5 kJ·mol-1)×2+(-285.8 kJ·mol-1)×2-
(-870.3 kJ·mol-1)=-488.3 kJ·mol-1
2△H2+2△H3 —△H1=(-393.5 kJ·mol-1)×2+(-285.8 kJ·mol-1)×2-
(-870.3 kJ·mol-1)=-488.3 kJ·mol-1
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