Write the equations represents enthalpy of formation of `H_(2)O`?

Answer

To write the equation that represents the enthalpy of formation of water (H₂O), we need to follow these steps:

### Step 1: Identify the constituent elements of water.
Water (H₂O) is composed of hydrogen (H) and oxygen (O). The standard state of hydrogen is diatomic gas (H₂), and the standard state of oxygen is diatomic gas (O₂).

### Step 2: Write the balanced chemical equation.
The enthalpy of formation is defined as the enthalpy change when one mole of a compound is formed from its elements in their standard states. For water, the balanced equation is:
\[ \text{H}_2(g) + \frac{1}{2} \text{O}_2(g) \rightarrow \text{H}_2O(l) \]

### Step 3: State the enthalpy change.
The enthalpy change for this reaction is denoted as ΔH_f° (standard enthalpy of formation). The value of ΔH_f° for water is typically negative, indicating that the formation of water from its elements is an exothermic process.

### Final Equation:
Thus, the complete equation representing the enthalpy of formation of water is:
\[ \text{H}_2(g) + \frac{1}{2} \text{O}_2(g) \rightarrow \text{H}_2O(l) \quad \Delta H_f° < 0 \]

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