Answer
4.730 MeV.
Work Step by Step
Calculate the Q-value, using data from Appendix B. We use atomic masses.
$$Q=\left( m_{\alpha}+m(^{16}_{8}O)-m(^{20}_{10}Ne) \right)c^2$$
$$ =\left(4.002603u+15.994915u-19.992440u\right)c^2\left( \frac{931.49MeV/c^2}{u}\right)$$
$$=4.730MeV$$
