The density of chromium metal is 7 g cm^{-3 | vedclass

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(A) The formula for density is $d = \frac{Z \cdot M}{N_{A} \cdot a^3}$.Rearranging to solve for $Z$: $Z = \frac{d \cdot N_{A} \cdot a^3}{M}$.Given: $d

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Body centred cubic

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(A) The formula for density is $d = \frac{Z \cdot M}{N_{A} \cdot a^3}$.Rearranging to solve for $Z$: $Z = \frac{d \cdot N_{A} \cdot a^3}{M}$.Given: $d = 7 \ g \ cm^{-3}$, $a = 300 \ pm = 300 	imes 10^{-10} \ cm = 3 	imes 10^{-8} \ cm$, $M = 52 \ g \ mol^{-1}$, and $N_{A} = 6.022 	imes 10^{23} \ mol^{-1}$.Substituting the values: $Z = \frac{7 	imes 6.022 	imes 10^{23} 	imes (3 	imes 10^{-8})^3}{52}$.$Z = \frac{7 	imes 6.022 	imes 10^{23} 	imes 27 	imes 10^{-24}}{52} \approx \frac{1138.158 	imes 10^{-1}}{52} \approx \frac{113.8}{52} \approx 2.18 \approx 2$.Since $Z = 2$, the unit cell is Body centred cubic $(BCC)$.

The density of chromium metal is $7 \ g \ cm^{-3}$. If the edge length of the unit cell is $300 \ pm$, identify the type of unit cell. (Atomic mass of $Cr = 52$)

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