Question

what else is produced when sodium carbonate decomposes?
na₂co₃ → na₂o +

Explanation:

Step1: Identify atoms in reactant

Sodium carbonate ($\ce{Na2CO3}$) has 2 Na, 1 C, 3 O atoms.

Step2: Identify atoms in known product

Sodium oxide ($\ce{Na2O}$) has 2 Na, 1 O atom.

Step3: Determine missing atoms

Subtract known product atoms from reactant: C: 1, O: 3 - 1 = 2. So the missing compound is $\ce{CO2}$ (1 C, 2 O).

Answer:

$\ce{CO2}$