chemistry question

Question

how do you write the equation for the standard heat of formation for: NaCl(s), HNO3 (g) BaCO3 (s)

Answer 1

Na(s) + 1/2 Cl₂(g) ==> NaCl(s)

1/2H₂(g) + 1/2 N₂(g) + 3/2 O₂(g) ==> HNO₃

Ba(s) + C(s) + 3/2 O₂(g) ==> BaCO₃(s)