Question

Calculate the number of atom in each
of the following (Given: Atomic mass
of I 127 u).
a. 254 u of iodine (
b. 254 g of iodine ()​

Answer 1

Explanation:

Answers are given in the image.

Answer 2

$\sf\large\pink{\underline{Solution}}$

$\sf\orange{No. of Atom = \dfrac{Given\:Mass}{Molar\:Mass} × N_{A}}$

$\sf{N_{A} → Avogadro Number ( i.e 6.022 × 10²³)}$

$\sf\underline\green{In \:254g\: of\: Iodine\: (I)}$

$\sf{No. \:of\: Atom = \dfrac{254}{127} × 6.022 × 10²³}$

$\sf{\fbox{→ 12.044 × 10²³\:atoms}}$

$\sf\bold{\underline{\pink{Note:-}}}$

$\sf{u = \dfrac{1}{6.022 × 10²³}}$

$\sf\underline\green{In \:254u\: of\: Iodine\: (I)}$

$\sf\small\orange{No.\: of\: Atom = \dfrac{254 × \dfrac{1}{6.022 × 10²³}}{127} × 6.022 × 10²³}$

$\sf\small\red{→\dfrac{254 × 1}{6.022 × 10²³×127}× 6.022 × 10²³}$

$\sf{\fbox{→ 2 \:atoms}}$