Question

what is the handbook value of concentration of calcium carbonate in hot water

Answer 1

Clasification of based on CaCO3 mg/L in ppm

carbonate hardness: 0 to 60 milligrams per liter as calcium carbonate (mg/L CaCO3) is classified as soft; 61 to 120 mg/L CaCO3 as moderately hard; 121 to 180 mg/L CaCO3 as hard;

calcium carbonate has a very low solubility in pure water (15 mg/L at 25°C), but in rainwater saturated with carbon dioxide, its solubility increases due to the formation of more soluble calcium bicarbonate. Calcium carbonate is unusual in that its solubility increases as the temperature of the water decreases

When heated above 840°C, calcium carbonate decomposes, releasing carbon dioxide gas and leaving behind calcium oxide – a white solid.

CaCO3(s)

→

CO2(g)

+

CaO(s)

Variation of Saturation calcium carbonate.Increasing the temperature tends to precipitate CaCO3 and yield a false pH Index With Temperature

Temp.°C. 0 10 20 30 40 50 60 70 80

K1K3/K2 10.5 7.28 5.07 3.55 2.46 1.78 1.29* 92* 0.68*

p(K1Ks /K2) 3.98 4.14 4.29 4.45 4.61 .75 4. 89* 5.0 5.17