What does this represent?
H2O + CO2 <-> H2CO3 <-> H+ + HCO3

answer:

Co2 h2o h2co3 H+ hco3

CO2 and water form carbonic acid or H2CO3, which is in equilibrium with bicarbonate (HCO3-)and hydrogen ions (H+). ... For example, an increase in CO2 will result in increased carbonic acid formation (H2CO3) which leads to an increase in both HCO3- and H+ (\pH)

answer:

H2O=Water(Hydrogen Oxygen)(2 Hydrogen 1 Oxygen)

CO2= Carbon Dioxide(2 Carbon and 2 Oxygen)

H2CO3=Carbon Acid(2 Hydrogen 3 Carbon and 3 Oxygen)

H=Hydrogen(1 Hydrogen)

HCO3=Bicarbonate(3 Hydrogen 3 Carbon 3 Oxygen)

Explanation:

I explained everything about these chemicals. Hope I helped out a lot