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

Question

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)

Answer 1

Given : atomic mass of I=127 u 

A. 254 u of iodine (I) 

Formula : number of atoms = $\frac{givenatomicmassofelement}{atomicmassofelement}$ 

$\therefore =\frac{254}{127}$ 

=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 =$\frac{givenmass}{molarmass}$ 

$\therefore =\frac{254}{127}=2$ 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  $1.2044\times {10}^{24}atoms$