Here's how to calculate the number of moles in 34.02 g of hydrogen peroxide (H₂O₂):

1. Find the molar mass of hydrogen peroxide:

* Hydrogen (H) has a molar mass of 1.01 g/mol.

* Oxygen (O) has a molar mass of 16.00 g/mol.

* H₂O₂ has a molar mass of (2 * 1.01 g/mol) + (2 * 16.00 g/mol) = 34.02 g/mol

2. Use the formula:

* moles = mass / molar mass

3. Plug in the values:

* moles = 34.02 g / 34.02 g/mol

* moles = 1 mol

Therefore, there is 1 mole of hydrogen peroxide in 34.02 g.