# In a fission reaction of U-235, there was a release of 9.20 x 10^1111 kJ of energy. What amount of mass in kilograms would have been lost?

Sep 14, 2016

$1.02 \times {10}^{-} 2 \cdot k g$

#### Explanation:

We use the famous mass energy equivalence formula, $E = m {c}^{2}$.

There were $9.20 \times {10}^{11} \cdot k J$ evolved in the fission of ""^235U.

Thus $E = 9.20 \times {10}^{11} \cdot k J = \text{mass} \times {\left(3.00 \times {10}^{8} m \cdot {s}^{-} 1\right)}^{2}$

And $\text{mass}$ $=$ $\frac{9.20 \times {10}^{11} \cdot k J}{3.00 \times {10}^{8} m \cdot {s}^{-} 1} ^ 2$

But $1 J$ $=$ $1 \cdot k g \cdot {m}^{2} \cdot {s}^{-} 2$

$\text{mass}$ $=$ $\frac{9.20 \times {10}^{14} \cdot k g \cdot \cancel{{m}^{2} \cdot {s}^{-} 2}}{{\left(3.00 \times {10}^{8}\right)}^{2} \cdot \cancel{{m}^{2} \cdot {s}^{-} 2}}$

Thus a mass of $1.02 \times {10}^{-} 2 \cdot k g$ would have been converted.

Please review my figures. You might get a more nuanced answer in the Physics section.