Question

1) Calculate the number of atoms in each of the following.
A) $52\text{moles of Ar}$

2) Calculate the number of atoms in each of the following.
B) $52\text{u of He}$

3) Calculate the number of atoms in each of the following.
C) $52g\text{of He}$

Answer 1

(1) Number of Ar atoms

$1\text{mole of Ar}=6.022\times {10}^{23}\text{atoms of Ar}$

Therefore,$52\text{mol of Ar}=52\times 6.022\times {10}^{23}\text{atoms of Ar}$
$=3.131\times {10}^{25}\text{atoms of Ar}$

Final Answer: Number of atoms in $52$ moles of Ar $=3.131\times {10}^{25}$

2) Number of He atoms

Mass of $1$ atoms of He $=4u$

Therefore, number of He atoms in $52u=\frac{52}{4}$

$=13$ atoms of He

Final Answer: Number of atoms in $52u\text{of He}=13$

3) Number of He atoms

$4g\text{of He}=6.022\times {10}^{23}$ atoms of He

$=7.8286\times {10}^{24}$ atoms of He

Therefore, numer of He atoms in $52g=\frac{52}{4}\times 6.022\times {10}^{24}$

Final Answer:Number of atoms in $52g\text{of He}=7.8286\times {10}^{24}$