求实验式和分子式 - Ans.fyi 參考答案

求实验式和分子式

2008-01-16 11:17 pm

一个1.53g的化合物,包含C,H和O. 系過度的氧气中燃烧.生成了2.24g CO2,0.918gH2O. 化合物的MOLAR MASS是60.03g/mol

a)求呢个化合物的empirical formula(实验式)系咩也?
b)\\求呢个化合物的molecular formula(分子式)系咩也?

回答 (1)

Uncle Michael

2008-01-17 2:39 am

✔ 最佳答案

a)
Molar mass of C = 12.01 g mol-1
Molar mass of H = 1.008 g mol-1
Molar mass of O = 16.00 g mol-1

Consider 1.53 g of the compound.
Mass of C = Mass of C in CO2 = 2.24 x (12.01/44.01) = 0.611 g
Mass of H = Mass of H in H2O = 0.918 x (2.016/18.016) = 0.103 g
Mass of O = 1.53 - (0.611 + 0.103) = 0.816 g

Mole ratio C : H : O
= (0.611/12.01) : (0.103/1.008) : (0.816/16)
= 1 : 2 : 1

Hence, empirical formula = CH2O

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b)
Let (CH2O)n be the molecular formula of the compound.
(12.01 + 1.008 x 2 + 16)n = 60.03
n = 2

Hence, molecular formula = C2H4O2

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