In a Certain Chemical Reaction $8.1 \times 10 ^ { - 19 } \mathrm {~J}$

In a certain chemical reaction, $8.1 \times 10 ^ { - 19 } \mathrm {~J}$ of energy is released per molecule formed. What is the difference in mass per molecule between the sum of the masses of the molecules of the reagents before the reaction and the mass of the molecules produced by the reaction? $\left( c = 3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } \right)$

A) $5.4 \times 10 ^ { - 32 } \mathrm {~kg}$
B) $9.0 \times 10 ^ { - 36 } \mathrm {~kg}$
C) $2.7 \times 10 ^ { - 27 } \mathrm {~kg}$
D) $8.1 \times 10 ^ { - 28 } \mathrm {~kg}$
E) $3.2 \times 10 ^ { - 27 } \mathrm {~kg}$