✔ 最佳答案
Molar mass of C = 12 g mol-1
Molar mass of H = 1 g mol-1
Molar mass of O = 16 g mol-1
Molar mass of CO2 = 12 + 16x2 = 44 g mol-1
Molar mass of H2O = 1x2 + 16 = 18 g mol-1
Fraction by mass of C in CO2 = 12/44
Fraction by mass of H in H2O = 2/18
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Unbalance equation :
CxHyOz + O2 → CO2 + H2O
In 3.41 g of the compound :
Mass of C
= Mass of C in CO2 formed
= 8.6 x (12/44)
= 2.345 g
Mass of H
= Mass of H in H2O formed
= 1.51 x (2/18)
= 0.168 g
Mass of O
= 3.41 - (2.345 + 0.168)
= 0.897 g
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In the compound, mole ratio C : H : O
= (2.345/12) : (0.168/1) : (0.897/16)
= 0.195 : 0.168 : 0.056
= 3.5 : 3 : 1
= 7 : 6 : 2
Hence, empirical formula = C7H6O2