Question

How many molecules are in 2.00 moles of `NO_2`?

Answer 1

`1.20xx10^24 "molecules"` of `NO_2`

Explanation:

We are going to use dimensional analysis (method that allows you to convert from one unit of measurement to another by cancelling out unwanted units) and the relationship below:

![http://www.slideshare.net/gbsliebs2002/moles-2313038]()

For questions like this I use the following technique:

`"Quantity Given" xx "Conversion Factor" = "Quantity Sought"`

`color(indigo)("Quantity Given:"` 2.00 moles

`color(coral)("Conversion Factor:"` `6.02xx10^23`

`color(orange)("Quantity Sought:"` molecules

Let's plug in our values:

`2.00cancel"mol"xx(6.02xx10^23"molecules")/(1cancel"mol")` = `1.20xx10^24 "molecules"`