Calculate the pH of Manzanita Lake in equilibrium with air at a year 2075 level of CO2 concentration of 700 ppm. Manzanita Lake is at a temperature of 10C, and is at an elevation of 4600 feet, where total air pressure = 0.85 atmosphere. For this question, you can assume that activities equal concentrations, i.e. that y = 1 for all species. For this question you cannot assume that the water in Manzanita Lake is in equilibrium with calcite. Henry's Law constant for CO2 KH.CO2 = [H2CO3]/PCO2 KH.co2 = 10-1.27 at 10C First Dissociation Constant for carbonic acid, HCO; = K21 = [H]. (HCO3-)[H2CO3] Ka1 = 10-6.46 at 10C Second Dissociation Constant for carbonic acid, H.CO; = K22 = [H-]-[CO32-1[HCO3-] Ka = 10-10.49 at 10C