To determine the number of moles of oxygen in 3.70 g of NaClO4, we need to know the molar mass of NaClO4 and the number of moles of oxygen per mole of NaClO4.

The molar mass of NaClO4 is calculated by adding the atomic masses of sodium (Na), chlorine (Cl), and four oxygen (O) atoms:

Molar mass of NaClO4 = 22.99 g/mol (Na) + 35.45 g/mol (Cl) + 4 × 16.00 g/mol (O)

= 106.44 g/mol

Now, let's determine the number of moles of NaClO4 in 3.70 g:

Moles of NaClO4 = Mass / Molar mass

= 3.70 g / 106.44 g/mol

= 0.0348 mol

Since there are four oxygen atoms in each formula unit of NaClO4, the number of moles of oxygen in 0.0348 mol of NaClO4 is:

Moles of oxygen = 4 moles O / 1 mole NaClO4 × 0.0348 mol NaClO4

= 0.1392 mol O

Therefore, there are approximately 0.1392 moles of oxygen in 3.70 g of NaClO4.