... Intermediate equations with known enthalpies are added together.
... Intermediate equations with known enthalpies are added together.
Hess's law is important to thermochemistry because it allows us to anticipate enthalpy changes of reactions that are too slow to realistically record, such as rusting or reactions that are too fast. Hess's law, stating that the enthalpy is the same regardless of the pathway, allows us to take known enthalpy values and substituting them in to find your target reaction's enthalpy change. Credentials: I almost have a high-school diploma :P, so don't quote me; u won't sound any smarter than I do. S14 ftw!
Because enthalpy is a state function and an extensive property.
if there is an increase in the number of gas molecules , then ^S > 0
To use Hess Law, one simply uses the known equations and their respective ∆H values, rearranges them as necessary to arrive at the target equation (unknown ∆H) and then adds the ∆H values to obtain the value for the target equation. This is possible because Hess Law applies to state functions which are independent of the path.
Intermediate equations with known enthalpies are added together
... Intermediate equations with known enthalpies are added together.
... Intermediate equations with known enthalpies are added together.
The enthalpy of a reaction does not depend on the reactant path taken.
... Intermediate equations with known enthalpies are added together.
Hess's law makes it possible to determine the overall enthalpy change for a chemical reaction by combining the enthalpy changes of multiple indirect reactions that add up to the desired reaction. This allows the prediction and calculation of the energy changes in chemical reactions, even if direct measurement of the reaction is not possible.
C - The enthalpy of reaction does not depend on the steps taken in the reaction. APEX --WXM--
All the reactions in a path are added together.
-572k
-572 k
1410 kJ
-572k