Question

How many moles of NO2 are there in 5.10 x 10 18*molecules of NO2?

Answer 1

Answer:

The first one, but there is a typo. Remember avogradro's number 6.02*10^23.

You just do 5.10x10^18 divided by avogadro's number

Explanation:

Answer 2

Answer:

A. 8.47 * 10^-6

Explanation:

Avogadro's number is used to convert moles to molecules, but it can also be used to convert moles into moles. Avogadro's number is 6.022 * 10^23 molecules per mole (or atom).

$5.10 * 10^{18} molecules * \frac{1 mol}{6.022 * 10^{23} molecules}$

The molecules units cancel leaving us with: $\frac{5.10 * 10^{18}}{6.022 * 10^{23}} mol$

This equals approximately 8.47 * 10^-6, which is the first option, A.

Hopefully this helped. Good luck!