Some amount of hydrogen peroxide (H2O2) breaks down to produce 3 molecules of oxygen (O2) and 6 molecules of water (H2O). How many atoms of hydrogen are there?

The answer to the question is ;

By counting the number of hydrogen in the decomposed hydrogen peroxide, there are a total 12 atoms of hydrogen in the reaction.

Explanation:

To solve the question, we note that

6H₂O₂ (l) → 6H₂O (l) + 3O₂ (g)

From the stoichiometry of the reaction, as it can be seen by balancing the equation that 6 moles of hydrogen peroxide liquid decomposes to produce 6 moles of liquid water molecule (H₂O) and 3 moles of oxygen gas molecules O₂.

Therefore, taking  count of hydrogen atoms in the reactant, there are 12 atoms of hydrogen atoms in the 6 molecules of hydrogen peroxide before the decomposition took place.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.