Calculate the number of atoms in 120 , g of c | vedclass

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Question

(A) $1$. For Calcium $(Ca)$: Atomic mass $= 40 \, g/mol$. Moles $= \frac{120 \, g}{40 \, g/mol} = 3 \, mol$. Number of atoms $= 3 	imes 6.022 	imes

Vedclass · Accepted Answer

$18.066 	imes 10^{23}$ atoms of $Ca$,$12.887 	imes 10^{23}$ atoms of $Fe$; $Ca$ has more; difference $= 5.179 	imes 10^{23}$

Vedclass · Answer

(A) $1$. For Calcium $(Ca)$: Atomic mass $= 40 \, g/mol$. Moles $= \frac{120 \, g}{40 \, g/mol} = 3 \, mol$. Number of atoms $= 3 	imes 6.022 	imes 10^{23} = 18.066 	imes 10^{23}$ atoms.$2$. For Iron $(Fe)$: Atomic mass $= 56 \, g/mol$. Moles $= \frac{120 \, g}{56 \, g/mol} \approx 2.143 \, mol$. Number of atoms $= 2.143 	imes 6.022 	imes 10^{23} \approx 12.905 	imes 10^{23}$ atoms (using precise division $120/56 \approx 2.1428$).$3$. Comparing the two,Calcium has more atoms.$4$. Difference $= (18.066 - 12.905) 	imes 10^{23} = 5.161 	imes 10^{23}$ atoms.

Calculate the number of atoms in $120 \, g$ of calcium and $120 \, g$ of iron. Which one has more number of atoms and what is the difference? (Given: atomic mass of calcium $= 40 \, u$ and iron $= 56 \, u$)

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