What will be the mass of oxygen needed to produce 90 L of carbon dioxide? pls help I'm failing chemistry because of pandemic

Which is a characteristic of mixtures?

Pl what kind of reaction is this? nahco3 + h2o → co2 + naoh + h2o -composition -decomposition -single replacement -double replacement im leaning more toward single replacement. if im wrong can you explain whyy?

What is the density, d, of a substance with a volume of v = 12.5 cm3 and a mass of m = 74.4 g ?