Question

How many atoms are in the sun if it is assumed the sun is composed of only molecular hydrogen and has a density of 1.42 g/cm? The radius of the sun is estimated to be 7x108 m and its volume can be found from V = nr? H D - lady po 7x 10!m Vitry3 cm²

Answer 1

Calculate the volume of the sun

V = 4/3 $\Pi$ r³

where,

V = volume of sun in cm³

$\Pi$ = 3.14159

r = radius of sun = 7 X 10⁸ m = 7 X 10¹⁰ cm

(1 m = 100 cm then 7 X 10⁸ m = 7 X 10⁸ X 100 = 7 X 10¹⁰ cm

substitute the value

Volume of sun = (4/3( X (3.14159) X  (7 X 10¹⁰ cm)³

Volume of sun = 1.436754 X 10³³ cm³

density of sun = 1.42 g/cm³

mass = volume X density

mass of sun =  1.436754 X 10³³ cm³ X 1.42 g/cm³

mass of sun = 2.04019 X 10³³ g

molar mass of H = 1.00794 g/mol

no. of moles = gm of compound X molar mass

moles of H atoms = 2.04019 X 10³³ g / 1.00794 g/mol

moles of H atoms = 2.024119 X 10³³ moles

no. of atoms = no. of moles X 6.022 X 10²³

no.of H atoms = 2.024119 X 10³³ X 6.022 X 10²³

= 1.2189245 X 10⁵⁷ atoms

Ans = No.of H atoms in sun = 1.2189245 X 10⁵⁷ atoms