Question

The number of molecules in 22.4cm cube of nitrogen gas STP is

Answer 1

No of moles = volume of gas at stp in llitres/22.4
No.of moles= 22.4 *22.4*22.4* 10 raised to power minus 3/22.4
No .if moles= 0.9
No of molecules =0.9*NA MOLECULES=5.4 *10 raised to power 23

Answer 2

Answer: $6.023\times 10^{26}molecules$

Explanation: According to avogadro's law, 1 mole of every gas occupies 22.4 L of gas at STP and conatins avogadro's number of particles $6.023\times 10^{23}$.

$22.4 L=22400 cm^3$     ($1L=1000cm^3$)

$22400cm^3$ contains = $6.023\times 10^{23}molecules$ of nitrogen gas.    

$22.4cm^3$ contains = $\frac{6.023\times 10^{23}}{22400}\times 22.4=6.023\times 10^{26}molecules$ of nitrogen gas.