[填空题]
Consider the following re.d)uv3ea sk.h w-1w* ( ku ;jp:tgkxzcaction:
$C_2H_4$(g)+$H_2$(g)→$C_2H_6$(g)
ΔH −136kJ mol$^{-1}$
ΔS −121JK$^{-1}$mol$^{-1}$
ΔG at 298K −99.9kJ mol$^{-1}$
1.1Explain why the enthalpy of formation of $H_2$ is 0kJmol$^{-1}$.
1.2Explain why the entropy change for this reaction is negative.
2.Explain how a reaction can be spontaneous with a negative entropy change.
3.Calculate the temperature at which this reaction is no longer spontaneous.
T= K
