# How many molecules are present in 1296 g of dinitrogen pentoxide #N_2O_5#?

##### 2 Answers

Approx

#### Explanation:

Moles of

Number of

Assume that:

n - number of moles

m - mass of substance

M - molar mass

1296 grams (m) of

Now you have to find the molar mass (M) of

Refer to your periodic table, just so you know that the molar mass (M) of Nitrogen is 14.0 g/mol and Oxygen 16.0 g/mol.

Therefore the molar mass (M) of

To find out the number of moles (n), look back at the

To find the number of molecules, use this formula:

Number of molecules = number of moles

Avogadro's number =

No of molecules in

=