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The density of lead is `11.35 g cm^(-3)` and the metal crystallizes with fee unit cell. Estimate the radius of lead atom. (At. Mass of lead `= 207 g mol^(-1) and NA = 6.02xx10^23 mol^(-1))`

Answer» Density of Lead `=11.35g//cm^3`
Atomic mass of lead `=270g//mol`
`N_A+6.02xx10^23mol^(-1)," Edges"=a" PM"=axx10^(-10)`
Valume `=a^3xx10^(-30)cm^3`
`"Density of the unit cell"=("Mass of unit cell")/(a^3xxN_Axx10^(-30))g//cm^3`
`11.35g//cm^3=(4xx207g//mol)/(a^3xx6.02xx10^23mol)g//cm^3`
`a^3=(4xx207cm^3)/(11.35xx6.02xx10^(-3))`
`a^3=121.18xx10^(-24)cm^3`
`a=4.948xx10^(-8)cm=494.8p m`.
`"In" Fcc,r=(sqrt2a)/4=(1.414xx494.8)/4=175 p m`


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