Post a New Question

Chemistry

posted by on .

The element Sc has hcp packing with a hexagonal unit cell. The density of scandium is 3.00E3 kg/m3 and the cell volume is 5.00E-26 L. Calculate the value of Avogadro's number to 3 significant figures based on these data. Note: the value may differ from the listed value.

  • Chemistry - ,

    I could convert 3.00E3 kg/m^3 to density of ?? g/cc.
    Then mass of unit cell is volume x density = xx grams.
    The hexagonal close packing produces 2 atoms/unit cell; therefore, that is the mass for 2 atoms. Divide by 2 to obtain the mass of 1 atom.
    Then look up the mass of Sc from the periodic table and that mass is the mass of a mole which contains Avogadro's number of atoms.
    Then,
    N = atomic mass x (1 atom/?? g) = xx atoms. I worked through this very fast and obtained about 6 x 10^23.
    Check my thinking. Check my work.

  • Chemistry - ,

    My answer that i got is 5.99E22

    i followed your step all the way till the periodic table..

    from there i got Sc atomic mass as 44.96 g

    then i multiply it by i atom/7.50E-22

    then i got the answer 5.99E22....is my steps and answer correct?

  • Chemistry - ,

    yes. That's the answer I obtaied also. On the others you posted above, I didn't go through any of them in detail. They follow the same general principles. But if you have trouble, post your work and tell us in detail about what you don't understand.

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question