Question

In the following chemical reaction, which element is shown to be violating the law of conservation of mass? C3H8 + 4O2 -> 3CO2 + 4H2O
A. C
B. H
C. O
D. none of the above; the equation is balanced.

Answer 1

Checking if it is balanced:

C             
3               3

H
8                  4*2 = 8

O
8                  3*2   + 4 = 6 + 4 = 10
8                   10

Only O is not balanced.

So O is violating the law.     Option C.

C. O