IN THE COMING DECADE NEW ORBITAL AND GROUND TELESCOPES WILL BE ABLE TO DETECT ATMOSPHERIC COMPOSITIONS OF TERRESTRIAL EXOPLANETS IN HABITABLE ZONES (HZ) OF THEIR STARS. ALTHOUGH COMPOSITIONS OF SURFACE ROCKS AND AQUEOUS PHASES MAY NOT BE OBSERVED IN FORESEEABLE FUTURE ATMOSPHERIC GASES COULD CONSTRAIN HABITABLE PLANETARY ENVIRONMENTS IF GAS-SOLID-AQUEOUS LINKS ARE UNDERSTOOD. ON SOLID HZ EXOPLANETS CHEMICAL INTERACTIONS BETWEEN GASES SURFACE WATER AND ROCKS COULD AFFECT THE COMPOSITION OF VOLATILE-BEARING PLANETARY ENVELOPES. THE ATMOSPHERIC CO2 ABUNDANCE IS SET BY A BALANCE BETWEEN SINKS AND A SUPPLY THROUGH DEGASSING. SINKS OF CO2 TO LIQUID AND SOLID PHASES ARE AFFECTED BY DISSOLUTION IN WATERS AND PRECIPITATION OF CARBONATES AND/OR CLATHRATES WHICH ARE INFLUENCED BY THE TEMPERATURE COMPOSITION AND ACIDITY (PH) OF SOLUTIONS. IN TURN CHEMISTRY OF AQUEOUS SOLUTIONS IS MAINLY AFFECTED BY THE COMPOSITION OF ALTERING ROCKS AND DISSOLUTION OF ATMOSPHERIC GASES. THE APPARENT DIVERSITY OF STAR COMPOSITIONS TOGETHER WITH COMPLEX SCENARIOS OF PLANET FORMATION AND EVOLUTION IMPLY A WIDE RANGE OF ROCK COMPOSITIONS. THESE COUPLED INFLUENCES COULD BE QUANTIFIED BY METHODS OF EQUILIBRIUM CHEMICAL THERMODYNAMICS CONSTRAINED BY FUNDAMENTAL CONSTANTS AND MASS BALANCES IN GAS-WATER-SOLID SYSTEMS ON HZ EXOPLANETS. THIS STUDY IS AIMED AT UNDERSTANDING EFFECTS OF ROCK COMPOSITION AND WATER/CO2/ROCK RATIOS ON AQUEOUS ACID-BASE CHEMISTRY SECONDARY MINERALOGY AND ABUNDANCE OF ATMOSPHERIC CO2 ON HZ EXOPLANETS. WE WILL CONSIDER WATER/CO2/ROCK INTERACTIONS ON WATERPOOR (DESERT) AND WATER-RICH (OCEAN) EXOPLANETS. WE WILL MODEL WATER-GAS-ROCK TYPE CHEMICAL INTERACTIONS AT SPECIFIED WATER/CO2/ ROCK RATIOS THROUGH CALCULATIONS OF CHEMICAL EQUILIBRIA IN CLOSED SYSTEMS AND SYSTEMS OPEN WITH RESPECT TO CO2. WE WILL CALCULATE ATMOSPHERIC CONCENTRATIONS OF CO2 AND LINK COMPOSITIONAL CHARACTERISTICS OF ROCKS WITH BUFFERING CAPACITIES OF ROCKS WITH RESPECT TO CO2. ROCK WILL BE PRESENTED BY REPRESENTATIVE TERRESTRIAL ROCKS AND COMPOSITIONS EVALUATED FROM COMPOSITIONS OF STARS. THE WATER/ ROCK RATIO WILL BE CHOSEN TO REFLECT THE OCEANIC DEPTH AND PERMEABILITY OF ROCKS. THE RESULTS WILL BE DISCUSSED IN TERMS OF OBSERVABLE ATMOSPHERIC CO2 LINKED TO CHEMISTRY MINERALOGY AND HABITABILITY OF AQUEOUS SYSTEMS. SIGNIFICANCE. THIS PROPOSAL LINKS AQUEOUS PROCESSES ON EXOPLANETS WITH QUANTITATIVE ASSESSMENTS OF HABITABILITY RELATED TO CO2 AND INORGANIC CHEMISTRY OF GAS-WATER-ROCK SYSTEMS IN THE VICINITY OF EXOPLANETARY SURFACES. THE WORK WILL EXPLORE HOW THE COMPOSITION OF ROCKS ON DIVERSE EXOPLANETS AND ROCK/CO2/WATER RATIOS AFFECT THE INORGANIC CHEMISTRY OF AQUEOUS ENVIRONMENTS. THE WORK IS RELEVANT TO THE HABITABLE WORDS PROGRAM BECAUSE IT DEALS WITH POTENTIALLY HABITABLE EXOPLANETS AND CONSIDERS WATER PHYSICS AND CHEMISTRY AS THEY RELATE TO HABITABILITY.