When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy?

Moderators: Chem_Mod, Chem_Admin

Kevin Tabibian 1A
Posts: 42
Joined: Fri Sep 29, 2017 7:06 am

When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy?

Postby Kevin Tabibian 1A » Sat Jan 13, 2018 6:45 pm

When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy? Online the definition of enthalpy is given as a measure of the internal heat of a system, but whenever we are talking about enthalpy it has to do with change. Sometime Professor call "ΔH" enthalpy and at other times he calls it change in enthalpy. Is enthalpy the measure of heat in a system or the measure of change of heat in a system?

Sabrina Dunbar 1I
Posts: 57
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy?

Postby Sabrina Dunbar 1I » Sat Jan 13, 2018 6:58 pm

The delta just means that it is the change in enthalpy, so H is enthalpy. However, that H value is to as important to us as the change in that value which you already stated is equal to q. Enthalpy is the measure of heat released or absorbed by a system at constant pressure, and the delta just makes that value a change. Hopefully this helps.

Bansi Amin 1D
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 1 time

Re: When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy?

Postby Bansi Amin 1D » Sat Jan 13, 2018 7:02 pm

H is the symbol for enthalpy, while delta H represents the change in enthalpy. Enthalpy is the measure of the internal energy of the system and shows the thermodynamic potential of the system. Internal energy is also the energy required to create the system. Delta H/the change in enthalpy is used to actually measure the enthalpy of the system because we can't do so with just the internal energy, we also need to account for the surroundings.

Annie Lieu-1H
Posts: 68
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

Re: When considering enthalpy (Δ H=q), is the letter "H" or "ΔH" Enthalpy?

Postby Annie Lieu-1H » Sat Jan 13, 2018 7:59 pm

H is enthalpy, and DeltaH is simply the change in enthalpy. However, we are interested in DeltaH because that is how we can measure the change in temperature (and subsequently, internal energy) because a change in the enthalpy of a system is equal to the heat released or absorbed at constant pressure.


Return to “Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)”

Who is online

Users browsing this forum: No registered users and 2 guests