Question

Calclate the number of:- i]molecules. [s=32] ii]atoms in 192g of sulphur. [s8]

Answer 1

Answer: 1. $4.52\times 10^{23}$  molecules

2. $36.1\times 10^{23}$ atoms  

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

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

Putting in the values we get:

$\text{Number of moles}=\frac{1928g}{256g/mol}=0.75moles$

1. molecules in 192 g of sulphur:

1 mole of sulphur $S_8$ contains=$6.022\times 10^{23}$  molecules

Thus 0.75 moles sulphur $S_8$ contain=$\frac{6.022\times 10^{23}}{1}\times 0.75=4.52\times 10^{23}$ molecules

2. atoms in 192 g of sulphur:

1 mole of sulphur $S_8$ contains=$8\times 6.022\times 10^{23}=48.2\times 10^{23}$  atoms  

Thus 0.75 moles of sulphur $S_8$  contain=$\frac{48.2\times 10^{23}}{1}\times 0.75=36.1\times 10^{23}$ atoms  

Answer 2

Answer:

1)0.75*6.023*10^23 molecules

2)6*6.023*10^23 atoms