[annazbylut]

Product from  reaction Na + O2 is Na2O2 or Na2O. It depend on   temperature, preesure or something else?

[Arkcon]

Here's a quick cut n' paste from Wikipedia:

Na₂O forms when sodium is treated with oxygen.

    4 Na + O₂ → 2 Na₂O

Burning sodium in air will produce Na₂O and about 20% sodium peroxide Na₂O₂.

    6 Na + 2 O₂ → 2 Na₂O + Na₂O₂

Pure Na₂O can be prepared by reaction of liquid sodium with NaNO₃.

    10 Na + 2 NaNO₃ → 6 Na₂O + N₂

In the case of burning sodium in air, what you'll get isn't rigidly defined by reaction conditions, as I recall, perhaps it's an equilibrium between Na₂O and Na₂O₂ ?

*[EDIT]*
Dang subscripts.

[Borek]

Na₂O forms when sodium is treated with oxygen.

    4 Na + O₂ → 2 Na₂O

Which is in obvious contradiction with "burning in air gives mixture". Peroxide article states "Sodium peroxide can be synthesized by direct reaction with sodium and oxygen at 130 - 200 °C."

[AWK]

But this range of temperature is difficult to keep during burning. Usually temperature without control is above 1000 C