Answer:
2
Explanation:
Based on the chemical equation, the number of molecules of hydrogen gas in the reactant side is 2.
This is indicated by the coefficient before reactant.
A molecule is a covalent compound that has discrete or separate units.
So H₂ is made up of two atoms of hydrogen that has been covalently bonded together by sharing their valence electrons.
From the reaction expression:
2 molecules of hydrogen gas combines with 1 molecule of oxygen gas to produce 2 molecules of water.
