Question

Calculate the no. of atoms in each of the following : 1

a) 16 moles of He (atomic mass of He = 4.0u)

b)16 g of He.​

Answer 1

Explanation:

(a)16moles of He contains

1mol of helium =6.022×10^23 atoms

16moles of He contains=16×6.022×10^23 atoms

(b)16g of He.

given mass=16g

molar mass=4g.

number of moles in 16gHe=16/4=4mol

1mol He contains=6.022×10^23 atoms

4mol of He contains=4×6.022×10^23 atoms

Answer 2

$\huge{\mathcal{\underline{\pink{AnsWer:-}}}}$

$\small\rm\bold{\boxed{Number\:of\:atoms\:=\:Moles\times\:Avagadro\:Number}}$

$\small\rm\bold{\boxed{Number\:of\:moles\:=\:\frac{Weight\:in\:grams}{Atomic\:mass}}}$

a) Number of moles = 16

Avagadro Number = 6.023 × 10²³

➥ Number of atoms = 6.023 × 10²³ × 16

➥Number of atoms = 96.368× 10²³

b) Weight in grams = 16 g

Atomic mass of He = 4

➥Number of moles = 16/4 = 4 mol

➥ Number of atoms = Number of moles × Avagadro number = 4 × 6.023 × 10²³ = 24.092 × 10²³

∴ Number of atoms in 16 mol of He is 96.368 × 10²³

Number of atoms in 16g of He is 24.092 × 10²³