2.
下面均是正丁烷与氧气反应的热化学方程式\(\rm{(25℃,101kPa)}\):
\(\rm{①C_{4}H_{10}(g)+ \dfrac {13}{2}O_{2}(g)═4CO_{2}(g)+5H_{2}O(l)\triangle H=-2}\) \(\rm{878kJ⋅mol^{-1}}\)
\(\rm{②C_{4}H_{10}(g)+ \dfrac {13}{2}O_{2}(g)═4CO_{2}(g)+5H_{2}O(g)\triangle H=-2}\) \(\rm{658kJ⋅mol^{-1}}\)
\(\rm{③C_{4}H_{10}(g)+ \dfrac {9}{2}O_{2}(g)═4CO(g)+5H_{2}O(l)\triangle H=-1}\) \(\rm{746kJ⋅mol^{-1}}\)
\(\rm{④C_{4}H_{10}(g)+ \dfrac {9}{2}O_{2}(g)═4CO(g)+5H_{2}O(g)\triangle H=-1}\) \(\rm{526kJ⋅mol^{-1}}\)
由此判断,正丁烷的燃烧热是\(\rm{(}\) \(\rm{)}\)