a) Xét hợp chất R₂(SO₄)_x

Ta có : \(\dfrac{2R}{96x}=\dfrac{20}{80}=\dfrac{1}{4}\Rightarrow R=12x\left(1\right)\)

b) Xét hợp chất R₂O_x

Ta có : \(\%R=\dfrac{2R}{2R+16x}\cdot100\%=\dfrac{R}{R+8x}\cdot100\%\left(2\right)\)

Thay ( 1 ) vào ( 2 ) , ta có : \(\%R=\dfrac{12x}{12x+8x}\cdot100\%=60\%\)

\(\frac{127}{128}\times x=1\)

\(\Rightarrow x=\frac{128}{127}\)

a) PTHH :4P + 5O₂ \(\rightarrow\) 2P₂O₅

\(n_P=\dfrac{m}{M}=\dfrac{42,6}{31}=1,37\left(mol\right)\)

\(\Rightarrow n_{O_2}=n_P\cdot\dfrac{5}{4}=1,37\cdot\dfrac{5}{4}=1,71\left(mol\right)\)

\(\Rightarrow V_{O_2}=n\cdot22,4=1,71\cdot22,4=38,3\left(l\right)\)

\(\Rightarrow V_{kk}=\dfrac{38,3\cdot100}{25}=153,2\left(l\right)\)

b) \(n_{P_2O_5}=n_P\cdot\dfrac{2}{4}=1,37\cdot\dfrac{2}{4}=0,685\left(mol\right)\)

\(\Rightarrow m_{P_2O_5}=n\cdot M=0,685\cdot142=97,27\left(g\right)\)