Why is Heat not a state property?

[Irene Oh 2A]

If enthalpy is considered a state property, I'm wondering why heat wouldn't be a state property if enthalpy is the amount of heat released or absorbed. I'm also not sure what it means by "it doesn't matter which path is taken."

[Howard Chu 1H]

Heat is not a state property because the values are just transferred and is a quantitative value. They are path-dependent.

[Renee Wen 3H]

I think in the Wednesday Lecture, Professor Lavelle mentioned that heat may not be a state property when it is not under constant pressure. However, otherwise, it would be, so it depends.

[janice]

Heat is not a state property because it is dependent on the path and energy changes that it took to get to the current state that it is in.

[Lale Kacharian 2K]

Heat capacity is a state property, however, heat itself is not because it depends on the path taken (the change of states).

[Ali Nosseir]

Heat isn't a state property because the different methods of heating something would yield different results when doing heat calculations. For example, a sample of water could be heated by either stirring it very very quickly or electrically heating it. By stirring the water, the kinetic energy is increasing, meaning it's heating up and by electrically heating the water, the transfer of heat energy occurs. When stirring the water, the q value, heat energy, would be equal to 0 whereas while electrically heating it, the q value would be greater than 0.

Because of this, heat isn't a state function, meaning the method something is being heated, affects its properties.

[Fatimah Jaffar 2J]

Heat isn't a state property because it is dependent on the pathway taken to reach the final point. Professor Lavelle illustrated this using the altitude example of how one hiker group used less energy to reach point B, but the other group expended more energy because they took a longer pathway even though both groups travelled from the same initial point to the same ending point.

[Emilia Yuja 3L]

Heat is not a state property since it takes into account what happens in the "middle of the path". A usual hint something might be a state property is that it has a triangle in front of it. Like change in temperature is ΔT and even entropy is ΔH. Heat does not have this feature.

[Jasmine Catalan 1H]

Heat is not a state property because the way you end up plying to heat to a certain object can lead to different results/calculations. Whereas enthalpy the amount of heat released or absorbed does not rely on the path taken. Therefore enthalpy is independent and heat is dependent.

[Bella Valente 2K]

If heat (q) is not a state property why is qp one?

[Gabriela Alfaro]

Heat isn't a state property because it depends on the path it followed to get to its final value. This means that in order to obtain heat, some process must have occurred. It could be a physical or chemical process for example.

[Thomas_Lehman_2D]

Heat is not a state property because it is path dependent and there is a transfer of energy involved, therefore it is not intrinsic to the system.

[Jess Kosz 1B]

I personally always thought heat and enthalpy were always the same in regards to systems, which made me confused when we learned that heat is not a state function but enthalpy is a state function. I think it’s easier to understand when you think of heat as something that can change in both directions over the course of a given amount of time and is a form of energy. Whereas, enthalpy just describes the amount of total heat transferred. Thus, heat itself is observed throughout an entire system while enthalpy only depends on the end and initial values.

[Anya Mostrenko 1F]

Calculating heat for a change in temperature of a substance is different (different equation) than for a phase change. In many change in heat calculations, both could occur and need to be taken into account. This means it depends on the path taken (not just final-initial) to calculate and discuss heat, therefore, it is not a state property.