H vs q

[VanessaZhu2L]

I am a little confused about the difference between H and q. I know that H is enthalpy and is a measure of heat, but how is that different from q?

[Colin Juett 2F]

My understanding is that enthalpy is basically the measure of heat per mole resulting from a reaction. Heat is a measure of energy transfer.

[Jonathan Haimowitz 3B]

ΔH is equal to q_p (heat at constant pressure).
On the other hand, q_v=ΔU (heat at constant volume equals change in internal energy).
So ΔH and q are the same at constant pressure but are not otherwise.
Note that it is ΔH and ΔU used in these equations, not plain H and U.
H (and also U) is a state function while q is not a state function.

[Kiran Marla]

H only equals q when it is qp (meaning that heat is added under constant pressure, which is the definition of enthalpy)

When it is qv, then the relationship is enthalpy=deltaU+nRdeltaT

[Lakshmi Davuluri 1E]

q is the heat consumed or released by the system, while enthalpy is the heat at constant pressure. q only equals delta H when q=qp, which is under conditions of constant pressure.

[Kiyoka Kim 3C]

The change in enthalpy is the amount of heat released or absorbed at a constant pressure while q represents the transfer of heat.

[Shreyank Kadadi 3K]

delta H, the enthalpy, is simply the measure of heat at constant pressure, whereas q is simply the heat not necessarily at constant pressure.

[Anh Trinh 1J]

Enthalpy is a state function that keeps track of losses of energy as expansion work during heat transfer at constant pressure (and the gain of energy if the process if compression). Meanwhile, heat is the energy transferred as a result of a temperature difference. Heat is not a state function because the energy transferred as heat during a change in the state of a system depends on how the change is brought about.

A change in the enthalpy of a system is equal to the heat released or absorbed at constant pressure.

[Lung Sheng Liang 3J]

Q is the amount of energy transferred while H is the energy released/absorbed. In a lot of situations H and Q are interchangeable.

[305405193]

Does any one have any good practice problems or YouTube videos for this topic to study for the final?

[Kiara Phillips 3L]

The way I think about is is delta H is the measure of heat at Constant Pressure but q is heat but not at any particular or constant pressure it just is. Outside of that I believe they will tell us when we are dealing with constant pressure so you can identify what formula to use.

[Kiara Phillips 3L]

Does any one have any good practice problems or YouTube videos for this topic to study for the final?

This video breaks it down a bit (https://youtu.be/6bi4_sAi0gE) hope this helps!

[MCalcagnie_ 1D]

H is a measure of heat at a constant pressure and represents the amount of heat released or absorbed, whereas q is a measure of the heat transferred.

[YuditGaribay3J]

I think H as the measure of internal energy and q would be heat transfer between the system and surroundings.

[AlbertGu_2C]

H is at constant pressure so it can be considered as a state function, while q depends on many things and therefore is not a state function

[Gabe_Ek 1G]

Does any one have any good practice problems or YouTube videos for this topic to study for the final?

This video breaks it down a bit (https://youtu.be/6bi4_sAi0gE) hope this helps!

This is a very helpful video as well, thank you!

[Sydney Sullivan 2J]

delta H and q are only the same when the reaction is at constant pressure!

[isha dis3d]

Q is the energy transfer due to thermal reactions such as heating water, cooking, etc. anywhere where there is a heat transfer. H, is the state of the system, the total heat content.

[Bai Rong Lin 2K]

I believe they would only be the same under constant pressure.

[Chinmayi Mutyala 3H]

H and q are the same under constant pressure. Otherwise, you'd get to different values for each. I'm not entirely sure how they're different conceptually.

[Sam Wentzel 1F 14B]

Q is heat transfer from a system, H is energy transfer from one side of a reaction to another