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Signs for enthalpy

Posted: Sun Jan 26, 2020 11:31 pm
by Riya Sood 4G
Are enthalpies always expressed as positive? Can they ever be negative?

Re: Signs for enthalpy

Posted: Sun Jan 26, 2020 11:38 pm
by Eesha Sohail 1D
Negative enthalpy would indicate that through a reaction, heat was lost. A reaction with negative enthalpy is the same as an exothermic reaction.

Re: Signs for enthalpy

Posted: Sun Jan 26, 2020 11:48 pm
by Alison Trinh 1E
Positive enthalpies are equivalent to endothermic reactions that take up heat. Enthalpies can be expressed as negative when a reaction is exothermic and therefore releases heat and warms the surroundings.

Re: Signs for enthalpy

Posted: Sun Jan 26, 2020 11:57 pm
by Jacob Motawakel
Enthalpies can be negative, indicating an exothermic reaction.

Re: Signs for enthalpy

Posted: Mon Jan 27, 2020 10:35 am
by Emily Burghart 1k
When a reaction has a negative enthalpy, it is considered ectothermic because it is releasing heat. You can think of how ecto sounds slightly like exit, and the negative sign as subtracting heat from a system and sending it into its surrounding environment. For endothermic, think of endo like enter. Endothermic enthalpies are positive because the heat must be entered, or added into a system. Heat is thus taken from its environment.

Re: Signs for enthalpy

Posted: Mon Jan 27, 2020 12:11 pm
by Hannah Romeo 1J
Enthalpy means the amount of heat transferred. In an exothermic reaction heat is released, therefore the enthalpy is negative. It is the reverse for an endothermic reaction.

Re: Signs for enthalpy

Posted: Mon Jan 27, 2020 12:14 pm
by sarahforman_Dis2I
Since enthalpy is a measure of the heat released or gained in chemical reactions, it can be negative. If a reaction has a negative enthalpy, that means it is losing enthalpy to the surroundings (releasing heat), meaning it is exothermic

Re: Signs for enthalpy

Posted: Mon Jan 27, 2020 12:27 pm
by 805097738
the sign of enthalpy indicates if the reaction is endothermic (positive) or exothermic (negative)

Re: Signs for enthalpy

Posted: Mon Jan 27, 2020 12:41 pm
by pmokh14B
Enthalpy is positive for endothermic reactions or indicates energy needs to be put in (i.e breaking bonds). negative enthalpy indicates exothermic reactions, or breaking bonds.