Carbon disulfide, \text{CS}_2, is a colorless, highly flammable liquid used in the manufacture of rayon and cellophane. A sample contains 0.0205 mol \text{CS}_2. Calculate the mass of carbon disulfide in the sample.
Solution:
Let us first find the molar mass of \text{CS}_2
The molar mass of \text{CS}_2 = 12.01 amu + (2\times 32.065) amu = 76.15 amu = 76.15 g/mol
(Note we multiplied the molar mass of sulfur by 2, because there are two sulfur atoms in the \text{CS}_2)
Now, we will calculate the mass of carbon disulfide in the sample. To do this, we will multiply the number of mol \text{CS}_2 in the sample by the molar mass of \text{CS}_2
0.0205 \text{mol CS}_2\times \frac{76.15 g}{1 mol}=1.5610 g
This question can be found in General Chemistry, 9th edition, chapter 3, question 3.40
