JEE MAIN - Chemistry (2024 - 30th January Morning Shift - No. 23)
$$0.05 \mathrm{~cm}$$ thick coating of silver is deposited on a plate of $$0.05 \mathrm{~m}^2$$ area. The number of silver atoms deposited on plate are ________ $$\times 10^{23}$$. (At mass $$\mathrm{Ag}=108, \mathrm{~d}=7.9 \mathrm{~g} \mathrm{~cm}^{-3}$$)
Answer
11
Explanation
$$\begin{aligned}
&\begin{aligned}
& \text { Volume of silver coating }=0.05 \times 0.05 \times 10000 \\\\
& =25 \mathrm{~cm}^3 \\\\
& \text { Mass of silver deposited }=25 \times 7.9 \mathrm{~g} \\\\
& \text { Moles of silver atoms }=\frac{25 \times 7.9}{108} \\\\
& \text { Number of silver atoms }=\frac{25 \times 7.9}{108} \times 6.023 \times 10^{23} \\\\
& =11.01 \times 10^{23}
\end{aligned}\\\\
&\text { Ans. } 11
\end{aligned}$$
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