Question

What is the mass in grams of a sample of 1.20 x 10 22 atoms of mercury?

Answer 1

4.0g Hg. I may be wrong and I really don't remember how to do it so I am not going to tell you my work, but I tried because I never did good on the chapter in chem.

Answer 2

The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³] (which is used as a standard in the world of moles).

Now,

          if     6.02 × 10²³ atoms are found in 1 mole of mecury
   then let   1.20 × 10²² atoms are found in     x

⇒     x  =    (1.20 × 10²²)  ÷  (6.02 × 10²³)

            =  0.0199 moles

Now, mass = moles × molar mass

∴ mass of Hg = 0.0199 mol ×  201 g/mol
                      = 4.001 g

∴ The mass in grams of a sample of 1.20 x 10²² atoms of mercury is ~ 4 g