Hydrogen gas (H2) and oxygen gas (O2) react to form liquid hydrogen peroxide (H2O2). Which statement is true about the reaction?
A.
The atoms of the reactants have combined to form a new substance.
B.
The two gases have mixed together, but a new substance has not formed.
C.
The product that is formed has the same physical properties as the reactants.
D.
The same atoms are present, so the chemical properties are the same.