Needed asap very much appreciated ! chemistry

12.00 moles of naclo3 will produce how many grams of o2? a) 256 g of o2 b) 576 g of o2 c) 288 g of o2

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2