Get Answers to all your Questions

header-bg qa

An element crystallizes in a f.c.c. lattice with cell edge of 400 \; pm. The density of the element is 7\; g\; cm^{-3}. How many atoms are present in 280\; g of the element ?

 

 

 

 
 
 
 
 

Answers (1)

Edge (a) =400 pm\; \; \; \; mfcc,z=4

Density =7g/cm^{3}

mass=280\; g

No.\; of\; atoms=?

Volume = (a)^{3}=(400pm)^{3}

                        =6.4\times 10^{-23}cm^{3}

Volume of 280\; g=\frac{mass}{density}

                           =\frac{280}{7}=40\; cm^{3}

No. of unit cells in 400cm^{3}=\frac{40}{6.4\times 10^{-23}}

                                               =6.25\times 10^{23}unit \; cells

Total no. of atoms in 280\; g=4\times 6.25\times 10^{23}

                                            =25\times 10^{23}atoms

 

Posted by

Sumit Saini

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads