Question

calculate the number of moles , the number of molecules, number of atom present in 0.051 gram of a Aluminium oxide​

Answer 1

Question:-

FinD:

• The no. of moles.
• The no. of molecules
• The no. of atoms

in 0.051 g of Aluminium oxide (That is Al2O3)

Required Answer:-

GiveN mass of Aluminium oxide = 0.051 g

Molecular mass = 2 × 27 + 3 × 16 = 102

No. of moles of Al2O3:

= Given Mass / Molecular mass

= 0.051 g / 102 g

= 0.0005 moles of Al2O3

We know that, 1 mole of any compound contains 6.022 × 10²³ molecules. Then$,$

No. of molecules in 0.0005 moles Al2O3:

= 0.0005 × 6.022 × 10²³

= 0.003011 × 10²³

= 3.011 × 10²⁰ molecules of Al2O3

1 molecule of Aluminium oxide contains 2 atoms of Aluminium and 3 atoms of oxygen. Total there is 5 atoms in each molecule.

No. of atoms in 1 molecule of Al2O3:

= 3.011 × 10²⁰ × 5

= 15.055 × 10²⁰

= 1.5055 × 10²¹ atoms in total.

Hence:-

• No. of moles = 0.0005 moles
• No. of molecules = 3.011 × 10²⁰ molecules
• No. of atoms = 1.5055 × 10²¹ atoms

Answer 2

✠ ɢɪᴠᴇɴ:–

• Mass of aluminium oxide = 0.051 g

✠ ᴛᴏ ғɪɴᴅ:–

• The number of moles
• The number of molecules
• The number of atom present

✠ sᴏʟᴜᴛɪᴏɴ:–

Molecular mass:—

→ 2 x 27 + 3 x 16

→ 102 g

Number of moles of A12O3:—

• Given mass/molecular mass

→ 0.051/102

→ 0.005 moles

Number of molecules present:—

→ 0.005 × 6.022 × 10²³

→ 0.003011 × 10²³

→ 3.011 × 10²⁰ molecules

Number of atoms present:—

→ 3.011 × 10²⁰ × 5

→ 15.055 × 10²⁰

→ 1.5055 × 10²¹ atoms

✠ ᴀɴsᴡᴇʀs:–

• Number of moles present is 0.005
• Number of molecules present is 3.011 × 10²⁰
• Number of atoms present is 1.5055 × 10²¹