Importance of State Symbols in Thermochemical Equations: Explained

[Jshua Monkoe]

1. Homework Statement
Why is it so important to show state symbols when writing chemical equations involving enthalpy changes?



3. The Attempt at a Solution
I guess:
from the thermochemical eqn deltaH=Sigma[H_{f}][products]-Sigma[H_{f}][reactants];
because the enthalpy of formation of a substance in different states is different,then this serves as a reason to denote the state symbols. Am I correct?monkoej@gmail.com

 

[Borek]

Heat of evaporation, heat of melting.

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methods

 

[Blueshift5]

Yes, you are correct. State symbols are important to include in thermochemical equations because they indicate the physical state of the substances involved in the reaction. This is important because the enthalpy change, or heat released/absorbed during a reaction, is affected by the physical state of the reactants and products. For example, the enthalpy of formation of a substance in its gaseous state will be different from its enthalpy of formation in its liquid state. Therefore, including state symbols allows for more accurate calculations of enthalpy changes in thermochemical equations. Additionally, state symbols also provide information about the reaction conditions, such as temperature and pressure, which can also affect the enthalpy change. Therefore, it is important to always include state symbols in thermochemical equations to ensure accuracy and completeness in the representation of the reaction.