# What is the number of molecules in 1.00 mol of iodine crystals?

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Is the answer 6.022 x 10^25 molec. of I2 ? or do I have double this answer, given that I2 is a diatomic molecule??

Is the answer 6.022 x 10^25 molec. of I2 ? or do I have double this answer, given that I2 is a diatomic molecule??

##### 1 Answer

#### Explanation:

The problem wants to make sure that you are familiar with the definition of **one mole** of a given substance.

In this case, you're dealing with a *covalent compound*, so you're looking for the number of molecules of iodine, **moles** of iodine crystals.

Now, a **mole** is defined as very, very large collection of particles. In order to have **moles** of iodine crystals, you need to have exactly **molecules** of iodine.

#color(blue)(ul(color(black)("1 mole I"_2 = 6.022 * 10^(23)"molecules I"_2# #-># Avogadro's constant

In your case, you will have

#"1.00 moles I"_2 = 6.02 * 10^(23)"molecules I"_2#

The answer must be rounded to three **sig figs**, the number of significant figures you have for the number of moles of iodine crystals.

Notice that each iodine molecule contains **atoms** of iodine, **mole** of iodine molecules contains **moles** of iodine atoms.

In

#overbrace(6.022 * 10^(23)color(red)(cancel(color(black)("molecules I"_2))))^(color(blue)(= "1.00 moles I"_2)) * "2 atoms of I"/(1color(red)(cancel(color(black)("molecule I"_2)))) = overbrace(1.20 * 10^(24)"atoms of I")^(color(purple)(="2.00 moles of I"))#

Once again, the answer must be rounded to three sig figs.