Calculate the mass fractions of the element oxygen in the substances

Calculate the mass fractions of the element oxygen in the substances (round the result to an integer) a) H2SO3 b) KOH c) N2O5 d) Na2CO3 e) Fe2O3

a) w (O) = m (O): Mr (H2SO3) × 100% = 48: 82 × 100% = 59%.
b) w (O) = m (O): Mr (KOH) × 100% = 16: 56 × 100% = 29%.
c) w (O) = m (O): Mr (N2O5) × 100% = 80: 108 × 100% = 74%.
d) w (O) = m (O): Mr (Na2CO3) × 100% = 48: 106 × 100% = 45%.
e) w (O) = m (O): Mr (Fe2O3) × 100% = 48: 160 × 100% = 30%.



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