Question

Which of the following contains highest number of molecules?
1. 44g of CO2. 2. 36g of H2O
3. 48g of O3. 4. 32g of SO4

Answer 1

2) 36 g H2O is the correct answer

Answer 2

Answer: 2. 36 g of $H_2O_$

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:

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

1. 44 g of $CO_2$

$\text{Number of moles}=\frac{44g}{44g/mol}=1mole$

Now 1 mole of $CO_2$ molecule contains = $6.023\times 10^{23}$ of molecules

2. 36 g of $H_2O_$

$\text{Number of moles}=\frac{36g}{18g/mol}=2mole$

Now 1 mole of $H_2O$ molecule contains = $6.023\times 10^{23}$ of molecules

2 moles of $H_2O$ molecule contains = $\frac{6.023\times 10^{23}}{1}\times 2=12.01\times 10^{23}$ of molecules

3. 48 g of $O_3$

$\text{Number of moles}=\frac{48g}{48g/mol}=1mole$

Now 1 mole of $O_3$ molecule contains = $6.023\times 10^{23}$ of molecules

4. 32 g of $SO_2$

$\text{Number of moles}=\frac{32g}{64g/mol}=0.5mole$

Now 1 mole of $SO_2$ molecule contains = $6.023\times 10^{23}$ of molecules

0.5 moles of $SO_2$ molecule contains = $\frac{6.023\times 10^{23}}{1}\times 0.5=3.01\times 10^{23}$ of molecules