Question

Balanced chemical reaction for sodium nitrate is heated

Answer 1

Sodium nitrate when heated to about 500°C will give Sodium nitrite and Oxygen gas.

But as we increase the temperature to 800°C, the formed Sodium nitrite will further decompose to form Sodium oxide and Nitrogen gas.

Heating at 500°C

2 NaNO₃ → 2 NaNO₂ + O₂

Heating till 800°C

4 NaNO₃ → 2 Na₂O + 2 N₂ + 5 O₂

Hope it helps!