How many moles of oxygen gas are required to combust 2.8 mol octane, c8h18, completely to co2 and h2o?

Can someone me with 1 to 4 plz. fast

Which statement best describes the he properties of iconic compounds ?

The size (radius) of an oxygen molecule is about 2.0 ×10−10m. make a rough estimate of the pressure at which the finite volume of the molecules should cause noticeable deviations from ideal-gas behavior at ordinary temperatures (t= 300k ). assume that deviatons would be noticeable when volume of the gas per molecule equals the volume of the molecule itself.