Products
Chemical reactions are characterized by the formation of new products, and the making and breaking of strong chemical bonds.
Density of gasoline is 0.737 g/mL and volume of tank is 13.0 gal.
Since, 1 US gal=3.78 L
Volume of tank in L will be:

Also, 1 L=1000 mL
Thus,

Mass of gasoline can be calculated as follows:
m=d×V
Here, d is density and V is volume thus,

Therefore, mass of gasoline will be
.
What would happen to the amount of matter on earth if mass were not conserved during changes of state?
Answer:
I think the primary producers start the flow of energy