The total mass before and after is the same
however water, H2O is 2 + 16 = 18 grams / mol
2 H2O ---> 2 H2 + O2
so for every 18*2 = 36 grams of water you better get
4 grams of H2 and 32 grams of O2
When water is electrolyzed, it splits into hydrogen and oxygen.
What can be said about the masses of the reactants and products?
4 answers
In addition to what Anoymous wrote, you also know that the volume of H2 gas formed will be twice the volume of oxygen gas formed.
The mass of water is equal to the combined mass of hydrogen and oxygen.
Anonymous is right. It is " The mass of water is equal to the combined mass of hydrogen and oxygen.