Most photos we see of Enya are the photos in the album booklets, or photos from magazines. As it is with all artists, Enya wears cosmetics in these photos, and sometimes the photos might be retouched to create a certain look.
Introduction Heat of formation is the enthalpy change when one mole of product is formed from its constituent elements under standard conditions. The equation for the formation of calcium carbonate from its elements under standard conditions is Ca(s)+C (graphite)+O2 (g) CaCO3(s).HfO (CO2 (g)) = -393.5 kJ mol -1 ?HfO (H2O (l)) = -285.5 kJ mol -1 Heat of formation of calcium carbonate = ?H1 + ?Hf (CO2 (g)) +?Hf (H2O (l))- ?H2 = -421+(-393.5)+(-285.5)- (-17.6) = -1082.4 kJ mol -1 In order to achieve the answer, Hess's law is used.
As a result, the carbonate fraction of hardness (expressed as CaCO 3 equivalents) is chemically equivalent to the bicarbonates of alkalinity present in water (Burton Jr. and Pitt 2002) in areas where the water interacts with limestone (Timmons et al. 2002).or alkalinity values up to 30 mg/L as CaCO 3, an endpoint pH of 4.9 is recommended (APHA et al. 1998). Endpoint pH values of 4.6 and 4.3 are recommended for alkalinities from 30 to 150 and 150 to 500 mg/L as CaCO 3, respectively (APHA et al.