Question

What is the number of molecules present in 1.12 dm^3 of nitrogen gas at STP​

Answer 1

`\huge\boxed{\sf No.\ of\ molecules = 3 * 10\²\² \ molecules}`

Step-by-step explanation:

Given Data:

Volume = v = 1.12 dm³ = 1.12 L

Density of nitrogen at STP = D = 1.25 g / L

Molar mass = M = 14 * 2 = 28 g / mol

Avogadro's Number =
`\tt{N_(A)}` = 6.023 * 10²³ mol⁻¹

Required:

No. of molecules = ?

Formula:

`\tt{No. \ of \ molecules = (Density * Volume)/(Molar\ Mass) * N_(A)}`

Solution:

No. of molecules = (1.25*1.12) / 28 * (6.023 * 10²³)

No. of molecules = ( 1.4 / 28 ) * 6.023 * 10²³

No. of molecules = 0.05 * 6.023 * 10²³

No. of molecules = 0.3 * 10²³

No. of molecules = 3 * 10²² molecules

`\rule[225]{225}{2}`

Hope this helped!

~AH1807