Final answer:
The mass lost in the chemical reaction is 5.00 x 10^-14 kg.
Step-by-step explanation:
Einstein's equation, E=mc², can be used to calculate the amount of mass lost in a chemical reaction. The equation states that energy (E) is equal to the mass (m) times the speed of light squared (c²). In this case, we have the energy released (45.0 kJ) and we need to determine the mass lost. Rearranging the equation, we have m = E/(c²). Plugging in the values, we get m = 45.0 kJ / (3.00 x 10^8 m/s)² = 45.0 x 10^3 J / (9.00 x 10^16 m²/s²) = 5.00 x 10^-14 kg.