Question

calculate the number of atoms present in 10g oxygen and 1.15g sodium ​

Answer 1

To find :

Number of atoms

Given :

• 10g Oxygen
• 1.15g Sodium

Formula used :

• Number of mole = mass ÷ molar mass
• Number of atoms = Number of moles × Atomicity × Avogadro's Number

Solution :

1) 10g Oxygen

• Molar mass of oxygen = 32 g/mol
• Atomicity = 2

Number of mole = 10 ÷ 32

Number of mole = 0.3125 mole

Number of atoms = Number of moles × atomicity × avogadro's numbers

Number of atoms = 0.3125 × 2 × 6.02 × 10²³

Number of atoms = 3.7625 × 10²³

2) 1.15g Sodium

• Molar mass of Sodium = 23g/mol
• Atomicity = 1

Number of mole = 1.15 ÷ 23

Number of mole = 0.05 mol

Number of atoms = 0.05 × 1 × 6.02 × 10²³

Number of atoms = 0.301 × 10²³

Number of atoms = 3.01 × 10²²

ANSWER :

• 10g Oxygen = 3.7625 × 10²³ atoms
• 1.15g Sodium = 3.01 × 10²² atoms