Please!!!Chem Question

[匿名]

2009-04-15 6:32 am

An uniknown compound Y is made up of carbon, hydrogen and chlorine only. On complete combustion of0.300g of Y, 0.272g of carbon dioxide and0.056dg of water are formed

A) Calxulate the empirical formula of Y
b) Give that the molecular mass of X is 97.0, determine the molecular formula ofY
c) Draw two possible stuctures for Y

Given C=12.00,H=1.00 Cl=35.5

回答 (1)

Uncle Michael

2009-04-15 8:57 am

✔ 最佳答案

a)
Mass fraction of C in CO2 = 12/(12 + 16x2) = 12/44
Mass fraction of H in H2O = (1x2)/(1x2 + 16) = 2/18

In 0.300 g of Y:
Mass of C = 0.272 x (12/44) = 0.0742 g
Mass of H = 0.056 x (2/18) = 0.0062 g
Mass of Cl = 0.300 - (0.0742 + 0.0062) = 0.220

Mole ratio C : H : Cl
= 0.0742/12 : 0.0062/1 : 0.220/35.5
= 0.0062 : 0.0062 : 0.0062
= 1 : 1 : 1

Empirical formula of Y = CHCl

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b)
Let (CHCl)n be the molecular formula.

(12 + 1 + 35.5)n = 97.0
n = 2

Hence, molecular formula of Y = C2H2Cl2

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c)
CH2=CCl2 and CHCl=CHCl
=

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