In representing chemical reactions with equations, the following are some general rules
reactants are written on the left
products are written on the right
catalysts are written on the arrow
the states of each molecules involved are written as subscripts in brackets. Where "aq" stands for aqueous, "l" stands for liquid, "g" stands for gas" and "s" stands for solid
From the above points, it can be deduced that hydrogen peroxide (H₂O₂) is the reactant but this reaction also suggests that H₂O₂ is been broken down (most likely thermally) since it is the only reactant and we have two products. O₂ gas and H₂O are the products in this reaction.
