The elements of a delta hf of kj\mole at standard temp and pressure

One mole of a substance forms Instead of standard atmospheric pressure and temperature from its pure elements{ conditions being the same} then this change and enthalpy is known as enthalpy of formation.

Explanation:

The equation of this formation can let us know what actually happens

ΔH = ΔHf(products) - ΔHf (reactants)

Hence we can say this change in enthalpy formation is the difference between the sum of product and sum of reactants.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

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