code: def alpha1_carbonate(pH):
      
      alpha1_carbonate = 1/((invpH(pH)/K1_carbonate) + 1 +
                            (K2_carbonate/invpH(pH)))
      return alpha1_carbonate
docs: Calculate the fraction of total carbonates in bicarbonate form (HCO3-)
  
      :param pH: pH of the system
      :type pH: float
  
      :return: Fraction of carbonates in bicarbonate form (HCO3-)
      :rtype: float
  
      :Examples:
  
      >>> from aguaclara.research.environmental_processes_analysis import alpha1_carbonate
      >>> round(alpha1_carbonate(10), 7)
      <Quantity(0.639969, 'dimensionless')>