A crystalline solid of a pure substance has a face-centred cubic structure with a cell edge of 400 pm. If the density of the substance in the crystal is 8 g cm^(-3), then the number of atoms present in 256 g of the crystal is Nxx10^24 . The value ofN is

A crystalline solid of a pure substance has a face-centred cubic struc

1.	A crystalline solid of a pure substance has a face-centred cubic structure with a cell edge of 400 pm. If the density of the substance in the crystal is 8 g cm^(-3), then the number of atoms present in 256 g of the crystal is Nxx10^24 . The value ofN is
Answer» <html><body><p><br/></p>Solution :`rho=(ZxxM)/(a^3xxN_0xx10^(-30))`where a is in pm and M in g `<a href="https://interviewquestions.tuteehub.com/tag/mol-1100196" style="font-weight:bold;" target="_blank" title="Click to know more about MOL">MOL</a>^(-1)` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a>=(4xxM)/((400)^3xx6xx10^23xx10^(-30))` or M=76.8<br/> <a href="https://interviewquestions.tuteehub.com/tag/moles-1100459" style="font-weight:bold;" target="_blank" title="Click to know more about MOLES">MOLES</a> in 256 g =`256/76.8`=3.33<br/> `<a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a>` No. of atoms =`3.33xx6xx10^23=2xx10^24`</body></html>