\(n_{H_2SO_4}=\dfrac{20}{98}=\dfrac{10}{49}\left(mol\right)\)
\(m_S=\dfrac{10}{49}\cdot32=6.53\left(g\right)\)
\(m_O=\dfrac{10}{49}\cdot4\cdot16=13.06\left(g\right)\)
nH2SO4= 20/98 = 10/49(mol)
=> mS= 10/49 x 32 \(\approx\) 6,531(g)
mO= 10/49 x 64 \(\approx\) 13,061(g)