Question

How many molecules are contained in a 7.20-g sample of dimethylmercury?

Answer 1

`1.88x10^(22)molecules (CH_3)_2Hg`

Step-by-step explanation:

Hello,

Dimethylmercury:
`(CH_3)_2Hg` has a molecular mass of:

`M_((CH_3)_2Hg)=12*2+1*6+200.59=230.6g/mol`

Now, the following mass-mole relationship including the Avogadro's number allows us to compute the requested molecules as follows:

`7.20g(CH_3)_2Hg*(1mol(CH_3)_2Hg)/(230.6g(CH_3)_2Hg) *(6.022x10^(23)molecules (CH_3)_2Hg)/(1mol(CH_3)_2Hg) =1.88x10^(22)molecules (CH_3)_2Hg`

Best regards.

Answer 2

The formula for dimethyl mercury is. HgC2H6 = (2x12) + (6x1) + (1x200.6) = 230.6
So the molar mass of dimethyl mercury is 230.6 g/mol.
Number of moles in 4.2g of dimethymercury = 4.2/ 230.6 = 0.0182 moles.
1 moles of dimethymercury contains 6.02 * 10^23
Hence 0.0182 moles contains X
X = 0.0182 * 6.02 * 10^23 = 0.10952 * 10^23 = 1.0952 * 10^22.