Answer:
A) 
Explanation:
m = Mass of water = 38.9
M = Molar mass of water = 18 g/mol
= Avogadro's number = 
The reaction of electrolysis would be
Number of moles of 
From the reaction it can be seen that 2 moles of gives 1 mole of 
So, number of moles of produced is
Number of molecules
So, of oxygen is produced.
Answer:
the atom
Explanation:
The bread and cheese separately represent the atom because both bread and cheese are different from one another and we cannot assume it as a molecule because molecules formed when the group of atoms combine together by making bonds with each other and we know that bread and cheese did not make bonds with each other, they only attached, so we called them atoms not molecule.
The principle that requires that a chemical equation be balanced would be the law of definite proportions. It <span>states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation. Hope this answers the question.</span>
