The enthalpy of formation of an element in its standard state is

JAMB Chemistry 2023 64 views

The enthalpy of formation of an element in its standard state is

  1. Zero ✓
  2. Negative
  3. Positive
  4. Depends on the element

Explanation

The enthalpy of formation measures energy change when a compound forms from its elements. For elements already in their natural state, no energy change occurs since nothing is being formed.

Standard state means the most stable form of an element at normal conditions. For example, oxygen as O₂ gas and carbon as graphite are in their standard states.

By definition, forming an element from itself requires zero energy change. This zero value serves as the reference point for measuring formation enthalpies of compounds.

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