Choose the coefficients that correctly balance the chemical equation: CaCO3(s) --->
_CaO(s) +
CO2(g).
O 1.1.1
O 1,2,2
O 1.2.1
O 2.2.1

Rank the four gases (air, exhaled air, gas produced from from decomposition of h2o2, gas from decomposition of nahco3) in order of increasing concentration of co2