A compoundmade up of two elements A and B has A=70%,B=30

Their relative number of moles in compound is 1.25 and 1.88, calculate:

[ i ] Atomic masses of the elements A and B

[ ii ] Molecular formula of the compond,if its molecular mass is found to be 160.

Asked by aniljhalic95136 | 9th Jul, 2019, 01:57: PM

Expert Answer:

Given:
 
A = 70%
 
B = 30%
 
We know,
 
Relative no. of moles  of an element
 
 
equals space fraction numerator percent sign of space the space element over denominator Atomic space mass end fraction

therefore space Atomic space mass space equals space fraction numerator percent sign of space the space element over denominator Relative space no. space of space moles space end fraction
 
(i)
Atomic space mass space of space straight A space equals space fraction numerator 70 over denominator 1.25 end fraction

space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 56

Atomic space mass space of space straight B space equals space fraction numerator 30 over denominator 1.88 end fraction

space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 15.95
 
(ii) Molecular formula of compound:
 
      Molecular weight of compound = 160
 

Empirical formula is A2B3.

Molecular formula = n(Empirical formula)

n = equals fraction numerator Molecular space mass over denominator Empirical space mass end fraction

equals fraction numerator 160 over denominator begin display style open square brackets open parentheses 56 cross times 2 close parentheses plus open parentheses 16 cross times 3 close parentheses close square brackets end style end fraction

equals 160 over 160

equals space 1

So, molecular formula is A2B3

Answered by Varsha | 9th Jul, 2019, 03:52: PM