# Qual è la formula del pentossido di dinitrogeno?

N_2O_5"

#### Spiegazione:

Lets have a look at the words involved:

dinitrogen and pentoxide.

The di e pent are common prefixes to words which signify numbers, but which numbers? Have a look at this table, and you will find that in this case they signify 2 and 5 respectively.

Using this knowledge (note that "penta" has the "a" removed for words starting with a vowel like "oxide"), it is possible to say that there are 2 nitrogen's and 5 oxygen's in this chemical equation, thus N ""_2O""_5"