Hey guys in this new video, we're going to continue with further calculations dealing with Gibbs free energy. So in this example, it says for mercury, the entropy of vaporization equals 58.5 kilojoules per mole. And then the entropy of vaporization equals 92.9 Jews over Kelvin's times moles at 25 degrees Celsius. Now I'm asking you does mercury boil at 3300 and 50 degrees Celsius and one atmosphere pressure. Now this question is similar to something we've seen earlier. What I'm really asking you for is calculating the normal boiling point of mercury. If we can find out the normal boiling point of mercury, we can see if this temperature is high enough for mercury to begin to boil. So remember if we're looking for the normal boiling point of mercury, we're going to assume that delta G zero is equal to zero. And doing this, we're going to say delta G zero equals delta H zero minus T delta S zero. Since this is equal to zero, we can now plug in all, we know we can plug in the delta H value as well as the delta S value So it's similar to something we've seen earlier. So this will be 58.5 kilojoules over moles minus t we don't know temperature. We're looking for it times, remember, enro um entropy of vaporization has to be in kilojoules just like delta H is in kilojoules. So divide that by 1000 gives us 0.0929 kilojoules over K times moles. So we're gonna subtract 58.5 kilojoules over moles. So negative 58.5 kilojoules over moles equals negative temperature times 0.0929 kilojoules over K times moles, we need to isolate our temperature. So we're going to divide out negative 0.0 929 kilojoules over K times moles. OK? So when we do that, this cancels out with this, the negative sign cancels out. We're gonna say that kilojoules and moles will cancel out with these kilojoules and moles leaving us with what units left Kelvin? So temperature here equals 6 29.7 Kelvin. OK. So we're gonna say here that is the normal boiling point of water. So that means the temperature has to be at minimum, this temperature for mercury to begin to boil. So we go back to the 350 degrees Celsius, we have to change it to Kelvin. So add 2 73.15 we get 6 23.15 Kelvin. And we can see that this temperature here is not high enough. It has to be a minimum of 6 29.7. The temperature we calculated earlier. So we're gonna say no, it does not boil, not hot enough has to be a little bit hotter than that.
