热化学方程式:C(石墨,s)+2H2(g)====CH4(g) H=aC(石墨,s)+2H2(g)====C2H2(g) H=bC(石墨,s)+2H2(g)====C2H4(g) H=c已知a>b>c,对于下列反应:C2H2(g)+H2(g)====C2H2(g) H=X2CH4(g)+C2H4+(g)+2H2(g) H=y判断正确的是:A::X
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![热化学方程式:C(石墨,s)+2H2(g)====CH4(g) H=aC(石墨,s)+2H2(g)====C2H2(g) H=bC(石墨,s)+2H2(g)====C2H4(g) H=c已知a>b>c,对于下列反应:C2H2(g)+H2(g)====C2H2(g) H=X2CH4(g)+C2H4+(g)+2H2(g) H=y判断正确的是:A::X](/uploads/image/z/2676306-66-6.jpg?t=%E7%83%AD%E5%8C%96%E5%AD%A6%E6%96%B9%E7%A8%8B%E5%BC%8F%EF%BC%9AC%EF%BC%88%E7%9F%B3%E5%A2%A8%2Cs%EF%BC%89%2B2H2%28g%29%3D%3D%3D%3DCH4%28g%29+H%3DaC%EF%BC%88%E7%9F%B3%E5%A2%A8%2Cs%EF%BC%89%2B2H2%28g%29%3D%3D%3D%3DC2H2%28g%29+H%3DbC%EF%BC%88%E7%9F%B3%E5%A2%A8%2Cs%EF%BC%89%2B2H2%28g%29%3D%3D%3D%3DC2H4%28g%29+H%3Dc%E5%B7%B2%E7%9F%A5a%EF%BC%9Eb%EF%BC%9Ec%2C%E5%AF%B9%E4%BA%8E%E4%B8%8B%E5%88%97%E5%8F%8D%E5%BA%94%EF%BC%9AC2H2%28g%29%2BH2%28g%29%3D%3D%3D%3DC2H2%28g%29+H%3DX2CH4%28g%29%2BC2H4%2B%28g%29%2B2H2%28g%29+H%3Dy%E5%88%A4%E6%96%AD%E6%AD%A3%E7%A1%AE%E7%9A%84%E6%98%AF%EF%BC%9AA%3A%3AX)
热化学方程式:C(石墨,s)+2H2(g)====CH4(g) H=aC(石墨,s)+2H2(g)====C2H2(g) H=bC(石墨,s)+2H2(g)====C2H4(g) H=c已知a>b>c,对于下列反应:C2H2(g)+H2(g)====C2H2(g) H=X2CH4(g)+C2H4+(g)+2H2(g) H=y判断正确的是:A::X
热化学方程式:C(石墨,s)+2H2(g)====CH4(g) H=a
C(石墨,s)+2H2(g)====C2H2(g) H=b
C(石墨,s)+2H2(g)====C2H4(g) H=c
已知a>b>c,对于下列反应:C2H2(g)+H2(g)====C2H2(g) H=X
2CH4(g)+C2H4+(g)+2H2(g) H=y
判断正确的是:
A::X>0 y<0 B:x<0 y>0 C:x>0 y>0 D:x<0 y>0
这个才是:C2H2(g)+H2(g)====C2H4 H=X
2CH4(g)==C2H4(g)+2H2(g) H=y
热化学方程式:C(石墨,s)+2H2(g)====CH4(g) H=aC(石墨,s)+2H2(g)====C2H2(g) H=bC(石墨,s)+2H2(g)====C2H4(g) H=c已知a>b>c,对于下列反应:C2H2(g)+H2(g)====C2H2(g) H=X2CH4(g)+C2H4+(g)+2H2(g) H=y判断正确的是:A::X
B:x<0 y>0 和D:x<0 y>0答案相同,由不稳定转化为稳定为放热,同样由稳定转化为不稳定为吸热,解析:
(1)C(石墨,s)+2H2(g)====CH4(g) H=a
(2)2C(石墨,s)+H2(g)====C2H2(g) H=b
(3)2C(石墨,s)+2H2(g)====C2H4(g) H=c
根据盖斯定律有则:C2H2(g)+H2(g)====C2H4 H=X可以看成是(3)-(2)即X=c-b
C,两个方程都是吸收热量吧,所以H都大于0
方程式有误,x和y的都有误
x:反应前后有机物一样……
y:没有等号
应该选A
因为H=a H=b H=c 都是吸热 所以 a b c 都大于0 又因为b>c 当二反应逆方向进行时 反应为放热 -b+c<0 则 X<0
而一反应 乘以二后 逆向进行 与三反应相加 可以得到 2CH4=C2H4+2H2 则 Y=-2a+c<0则 该题无答案