HgC2H6

How many molecules are contained in a 5.10-g sample of dimethylmercury?

What is the percentage of mercury (by mass) in the sample?

The number of molecules = 1.33 * 10∧22 molecules

percentage of mercury = 87%

Explanation:

Given dа ta:

mass of dimethyl mercury = 5.10 g

number molecules of dimethyl mercury in 5.10 g = ?

percentage of mercury = ?

Solution:

First of all we will calculate the molar mass of dimethyl mercury.

molar mass of HgC2H6 = 1*200.6 + 2*12 + 6*1 = 230.6 g/mol

we know that,

230.6 g of HgC2H6 = 1 mol = 6.02 * 10∧23 molecules.

so

For the 5.10 g of sample:

5.10 g/230 g/mol = 0.022 moles of HgC2H6

now we will multiply these number of moles with Avogadro number to get number of molecules in 5.10 g of sample.

0.022 * 6.02 * 10∧23 molecules = 0.133 * 10∧23 molecules or

1.33 * 10∧22 molecules.

Percentage of mercury:

Formula:

percentage = (atomic number of Hg * total number of atoms of Hg / molar mass of HgC2H6) * 100

% age of Hg = (200.6 g/mol * 1 / 230.6 g/mol) * 100

%age of Hg = 0.869 * 100

%age of Hg = 86.99 % or 87 %