Decomposition is the answer to your question.
Radioactivity refers to the natural transmutation, whereas transmutation refers to the change of one chemical element into another
The theoretical yield is 160 g H₂O.
<em>Moles of H₂</em> = 18 g H₂ × (1 mol H₂/2.016 g H₂) = 8.93 mol H₂
<em>Moles of H₂O</em> = 8.93 mol H₂O × (2 mol H₂O/2 mol H₂) = 8.93 mol H₂O
<em>Theoretical yield</em> of H₂O = 8.93 mol H₂O × (18.02 g H₂O/1 mol H₂) = 160 g H₂O