Question

Question #00f88

Answer 1

`2.41xx10^24" atoms"`

Explanation:

You are given `4.00` moles of strontium. We also are taught that a mole is just an amount of things. Just like the word "dozen" means "12 things", the word "mole" just means `602` hexillion things. This is Avogadro's number and is written

`1" mole"=6.02xx10^23` things, or this case, atoms.

This equation gives us two possible conversion factors:

Either `(1" mole")/(6.02xx10^23" atoms")`, or `(6.02xx10^23" atoms")/(1" mole")`

Use the conversion factor which cancels out the "moles" and keeps the number of atoms. So this is the conversion factor with moles in the denominator.

`4.00cancel(" moles")xx(6.02xx10^23" atoms")/(1cancel(" mole"))=24.1xx10^23" atoms"`

ANSWER: `2.41xx10^24" atoms"`