# A sample of chlorine gas has a mass of 39.2 grams. How many #Cl_2# molecules are there in the sample?

##### 2 Answers

See below.

#### Explanation:

This problem is a classic *stoichiometry* problem. To solve this problem, you want to have your periodic table (to find the molar mass (g/mol) of Cl2), calculator, and *Avogadro's number* handy. The approach is outlined below:

Hence, the answer is *Avogadro's number*, and it can be referred to as *the number of molecules in one mole of that substance*. Also, I calculated

I hope that helps!

There are

#### Explanation:

There are

**Given mass:**

**Molar mass:**

**Determine the moles #"Cl"_2"#.**

**Determine molecules of #"Cl"_2"#.**