Helppppppppppppppppp

\begin{array}{|c|c|c|}
\hline \rm Chất&\rm Số\ mol&\rm Klg\ mol&\rm Khối\ lượng&\rm Cách\ tính\\
\hline \rm Nước&2&18&36&m_{H_2O}=2×18=36(g)\\
\hline \rm Khí\ oxygen&0,5&32&16&n_{O_2}=\dfrac{16}{32}=0,5(mol)\\
\hline \rm Khí\ nitrogen&1&28&28&n_{N_2}=\dfrac{28}{28}=1(mol)\\
\hline \rm Muối\ ăn&0,4&58,5&23,4&m_{NaCl}=0,4×58,5=23,4(g)\\
\hline \rm Magnesium&0,5&24&12&n_{Mg}=\dfrac{12}{24}=0,5(mol)\\
\hline\end{array}