Ozone, O3
 methane, CH4
 oxygen gas, O2
 All of these may be classified as
 A) ionic compounds 
 B) covalent compounds 
 C) inorganic compounds 
 D) nonreactive compounds
 The correctly balanced equation for H₂O₂ → H₂O + O₂ is
 A) H₂O₂ → 2H₂O + O₂ 
 B) H₂O₂ → H2O + 2O₂ 
 C) 2H₂O₂ → 4H₂O + O₂ 
 D) 2H₂O2 → 2H₂O + O₂