Question

1A: a certain metal crystallizes in a bcc lattice. the atoms have a radius of 1.983 A and the metal has a density of 5.253 g/ml What is the atomic symbol of this metal?

1B: Tartaric acid is a white, crystalline organic acid that occurs naturally in many fruits (mostly in grapes). The molar mass of tartaric acid is 150.087 g/mol and its emperical formula is C2H3O3. Draw a Lewis structure for tartaric acid.

Answer 1

1A.

a   = 4r/3

      = 4*1.983*10^-8/1.732

       = 4.6*10^-8 cm

in BCC Z = 2

d   = ZM/N * a^3

M     = d*N*a^3/Z

         = 5.253*6.023*10^23*(4.6*10^-8)^3/2   = 154g/mole

metal is promithium

1B.

molecular formula = (empirical fromula)n

               n              = molecular mass/empirical formula mass

                                 =150.087/75   = 2

molecular formula   = (C2H3O3)2 = C4H6O6