Which of the following represents the formation equation for barium nitrate, Ba(NO₃)₂?

• A. Ba²⁺ (aq) + 2 NO₃^– (aq) → Ba(NO₃)₂ (aq)
• B. Ba(NO₃)₂ (aq) → Ba (s) + N₂ (g) + 3 O₂ (g)
• C. Ba (s) + N₂ (g) + 3 O₂ (g) → Ba(NO₃)₂ (aq)
• D. Ba (s) + 2 N (g) + 6 O (g) → Ba(NO₃)₂ (aq)

Answer: (C)

Verified step by step guidance

1. Understand the concept of a formation equation: A formation equation represents the formation of a compound from its elements in their standard states.
2. Identify the elements involved in the formation of barium nitrate, Ba(NO3)2. These elements are barium (Ba), nitrogen (N), and oxygen (O).
3. Determine the standard states of these elements: Barium is a solid (Ba(s)), nitrogen is a diatomic gas (N2(g)), and oxygen is a diatomic gas (O2(g)).
4. Write the balanced chemical equation for the formation of barium nitrate from its elements in their standard states. This involves combining barium, nitrogen, and oxygen to form Ba(NO3)2.
5. Check the stoichiometry: Ensure that the number of atoms of each element is balanced on both sides of the equation. For Ba(NO3)2, you need 1 Ba, 2 N, and 6 O atoms, which corresponds to the equation: Ba(s) + N2(g) + 3 O2(g) → Ba(NO3)2(aq).