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4) solve problems

D. Calculate the number of atom in each of the following (Given : Atomic mass of I = 127 u).

a. 254 u of iodine (I)

b. 254 g of iodine (I)
in Chapter 1: Some Basic Concepts of Chemistry by Expert (10.7k points)
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Given : atomic mass of I=127 u 

A. 254 u of iodine (I) 

Formula : number of atoms = \(given \space atomic \space mass \space of \space element\over atomic \space mass \space of \space element\) 

\(\therefore \space ={254\over 127}\) 

=2 atoms 

254 u of iodine (I) consist of  2 atoms of I 

B. 254 g of iodine (I)

we know the Molar mass of iodine  which is 127 g 

Formula :: no of moles =\(given\space mass\over molar \space mass\) 

\(\therefore\space = {254\over 127 }=2\) moles 

therefore , number of atoms = n× Avogadro's number 

=2\(\times 6.022\times 10^{23}\) atoms =\(1.2044\times 10^{24} atoms\)

254 g of iodine (I) consist of  \(1.2044\times 10^{24} atoms\)

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