Question

Un amestec de diclorometan si tetraclorura de carbon contine 87,65% clor. Procentul de clorura de metilen din amestec este:
A. 52,47% B. 47,53% C. 63,28% D.50% E. 87,65%

Answer 1

amintesc: n=m/M => m=n*M
notam raportul molar CH2Cl2:CCl4=x:y
mCH2Cl2=85x si mCCl4=154y
mamestec........100%
mCl.................87,65%
=>
85x+154y...........100%
71x+142y........87,65%
(x+2y)*71*100=(85x+154y)*87,65
7100x+14200y=7450,25x+13498,1y
350,25x=701,9y => x=2y => x:y=2:1
85*2+154...........100%
85*2........................z%
x=170*100/324=52,47% diclorometan => a)