6.39 The main buffer in the blood consists primarily of hydrogen carbonate ions (HCO3)and H3O+ions in equilibrium with water and CO2 : H3O+(aq)+HCO3(aq)2H2O(l)+CO2(aq)K=7.9107 This reaction assumes that all H2CO3 produced decomposes completely to CO2 and H2O. Suppose that 1.0L of blood is removed from the body and brought to pH=6.1. (a) If the concentration of HCO3is 5.5molL1, calculate the amount (in moles) of CO2 present in the solution at this pH. (b) Calculate the change in pH that occurs when 0.65molH3O+is added to this sam ple of blood at this pH (that is, pH=6.1 ). See Box 6G.1