CHEMISTRY OXIDATION NUMBERS
please help me solve only 3 of those oxidation numbers

NO2
Cr2O72-
KCl
NH3
CaH2
SO42-
Na2O2
SiO2
CaCl2

Agas in a balloon at constant pressure has a volume of 160 ml at -125*c. what is its volume at 29.0*c?

Select each correct answer. more than one answer may be correct. which of the following is a characteristic of unicellular organisms? they can possess tissues and organs. all of their functions are performed by a single cell. they are usually microscopic. each of their cells is specialized to perform a specific function.

In the reaction h2co3 (aq) + 3nh3 (aq) = 2 nh4+ (aq) + co3 2-, how many electrons are transferred?