Question

How many molecules would there be in 3.500 grams of carbon disulfide?

Answer 1

Carbon disulfide:

$CS_2$

First, we need to know this:

1 mol of CS2 = 76.13 g (this value is obtained from the molar mass)

Also,

1 mol of CS2 = 76.13 g = 6.022 x 10^23 formula units ( molecules, atoms, etc.)

We have been asked for the number of molecules in 3.500 g of CS2.

Procedure:

75.13 g of CS2 ---------------- 6.022 x 10^23 molecules of CS2

3.500 g of CS2---------------- x

$x\text{ = }\frac{3.500gx6.022x10^{23}molecules}{75.13\text{ g}}=2.805x10^{22}molecules_{}$

Answer: 2.805x10^22 molecules of CS2