Questions: The stoichiometric coefficient of the product in a formation reaction must be 1 . Write a balanced chemical equation for the standard formation reaction of solid mercury(II) oxide ( HgO ).

Solution Steps

A formation reaction involves forming one mole of a compound from its elements in their standard states. For mercury(II) oxide (HgO), the elements involved are mercury (Hg) and oxygen (O).

• Mercury (Hg) is a metal and exists as a liquid in its standard state.
• Oxygen (O) exists as a diatomic gas, \( \text{O}_2 \), in its standard state.

The unbalanced formation reaction for solid mercury(II) oxide from its elements is: \[ \text{Hg (l)} + \text{O}_2 (g) \rightarrow \text{HgO (s)} \]

To balance the equation, ensure that the number of atoms of each element is the same on both sides. Since the stoichiometric coefficient of the product must be 1, adjust the reactants accordingly:

• 1 mole of Hg is needed.
• Since \( \text{O}_2 \) is diatomic, only half a mole of \( \text{O}_2 \) is needed to provide 1 mole of O atoms.

The balanced equation is: \[ \text{Hg (l)} + \frac{1}{2} \text{O}_2 (g) \rightarrow \text{HgO (s)} \]

Final Answer