2CuO + O2 -> 2CuO

CuO - 2g
O2 - ?

From the balanced equation, we can see that 1 mole of O2 reacts with 2 moles of CuO. Therefore, the amount of O2 required to react with 2g of CuO can be calculated using the molar masses:

Molar mass of CuO = 63.55 + 16.00 = 79.55 g/mol
Molar mass of O2 = 2*16.00 = 32.00 g/mol

1 mole of CuO = 79.55 g
2 g of CuO = (2/79.55) moles of CuO

From the reaction, 1 mole of O2 reacts with 2 moles of CuO. Therefore, the amount of O2 required can be calculated as follows:

(2/79.55) moles of CuO * (1 mole O2 / 2 moles CuO) = 2/159.1 moles O2

Now, we can convert this into grams of O2:

(2/159.1) moles * 32.00 g/mol = 0.402 g

Therefore, 0.402 grams of O2 is required to react with 2 grams of CuO.