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CALCIUM - Ca

Properties of Calcium:

Alkaline earth metal, silver-white, ductile, fairly hard. In humid air is covered with a film of oxide-hydroxide. Colors the flame of gas burner to brown-red. Reactive, reacts with oxygen, nitrogen, hydrogen, halogens and other non-metals by heating. A strong reducing agent, reacts with water, dilute acids, ammonia.

 

Molar mass	g/mol	40.078
Density	g/cm3	1.54
Melting point	°C	842
Boiling point	°C	1495

 

Methods for the preparation of Calcium:

CaH2 = Ca + H2 (over 1000°C).

4CaO + 2Al = 3Ca + (CaAl2)O4 (1200°C).

3CaCl2 + 2Al = 3Ca + 2AlCl3 (600-700°C).

CaCl2(liquid) → Electrolysis → Ca(on cathode) + Cl2↑(on anode).

 

Сhemical reactions with metal Calcium:

Ca + 2H2O = Ca(OH)2↓ + H2↑ (normal temp.),

2Ca + H2O(vapor) = CaO+CaH2 (200-300°C).

Ca + 2HCl(diluted) = CaCl2 + H2↑.

4Ca + 10HNO3(diluted) = 4Ca(MO3)2 + N2O↑ + 5H2O.

4Ca + 10HNO3(highly diluted) = 4Ca(NO3)2 + NH4NO3 + 3H2O.

Ca + H2 = CaH2 (500-700°C).

2Ca + O2 = 2CaO (over 300°C, burning on air).

Ca + E2 = CaE2 (normal temp., E = F; 200-400°C, E = Cl, Br, I).

Ca + S = CaS (150°C).

3Ca + N2 = Ca3N2 (200-450°C, burning on air),

3Ca + 2P(red) = Ca3P2 (350–450°C).

Ca + 2C(graphite) = CaC2 (550°C).

Ca + 6NH3(gas) = [Ca(NH3)6](e−)2(yellow) [normal temp.],

6Ca + 2NH3(gas) = Ca3N2 + 3CaH2 (600-650°C).

Ca + 6NH3(liquid) = [Ca(NH3)6](blue) [-40°C, in the atm. of Ar],

Ca + 2NH3(liquid) = Ca(NH2)2↓ + H2↑ (catalyst Pt).