Em tham khảo nha:
\(\begin{array}{l}
{K_2}C{O_3}:\\
{M_{{K_2}C{O_3}}} = 39 \times 2 + 12 + 16 \times 3 = 138\,dvC\\
\% {m_K} = \dfrac{{39 \times 2}}{{138}} \times 100\% = 56,52\% \\
\% {m_C} = \dfrac{{12}}{{138}} \times 100\% = 8,7\% \\
\% {m_O} = 100 - 56,52 - 8,7 = 34,78\% \\
Al{(OH)_3}\\
{M_{Al{{(OH)}_3}}} = 27 + 16 \times 3 + 1 \times 3 = 78\,dvC\\
\% {m_{Al}} = \dfrac{{27}}{{78}} \times 100\% = 34,62\% \\
\% {m_O} = \dfrac{{16 \times 3}}{{78}} \times 100\% = 61,54\% \\
\% {m_H} = 100 - 34,62 - 61,54 = 3,84\% \\
S{O_2}:\\
{M_{S{O_2}}} = 32 + 16 \times 2 = 64dvC\\
\% {m_S} = \dfrac{{32}}{{64}} \times 100\% = 50\% \\
\% {m_O} = 100 - 50 = 50\%
\end{array}\)
