In this equation, what should be the coefficients of the reactants and products? i2 + o2 → i4o9

Which statement describes both homogeneous mixtures and heterogeneous mixtures?

When svante arrhenius first proposed his acid-base theory, he was a doctoral candidate. his professors thought his ideas were unfounded. within a decade, the arrhenius theory of acid-base was widely accepted and praised within the scientific world. arrhenius defined acids as compounds having ionizable hydrogen and bases as compounds with ionizable a) barium. b) hydronium. c) hydroxide. d) oxygen.

Avariable that is not being directly tested during an experiment should be