How does the law of conservation of mass apply to this: C2H4+O2→ 2H2O+2CO2 A. Only the oxygen needs to be balanced. There are equal numbers of hydrogen and carbon
b Each element needs to be balanced.
C. The equation needs to be balanced. There are fewer oxygen atoms in the equation than hydrogen or carbon.
D. e law of conservation of mass has already been applied. There is an equal number of each element on both sides of the equation.