Question

calculate the number of molecules and number of atoms present in 11.2 litres of oxygen at stp

Answer 1

No.of molecules=(6.022×10^23)/2=3.011×10^23
No.of atoms = 3.011×10^23=6.022×10^23 ( since oxygen gas is diatomic)

Answer 2

Answer: $3.01\times 10^{23}$ molecules and $6.023\times 10^{23}$ atoms of oxygen

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

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given volume}}{\text {Molar volume}}$

$\text{Number of moles}=\frac{11.2L}{22.4L}=0.5moles$

1. 1 mole of $O_2$ molecule contains = $6.023\times 10^{23}$ of molecules

0.5 mole of $O_2$ molecule contains = $\frac{6.023\times 10^{23}}{1}\times 0.5=3.01\times 10^{23}$ molecules

2. 1 mole of $O_2$ molecule contains = $2\times 6.023\times 10^{23}=12.05\times 10^{23}$ atoms of oxygen

0.5 mole of $O_2$ molecule contains = $\frac{12.05\times 10^{23}}{1}\times 0.5=6.023\times 10^{23}$ atoms of oxygen