Calcium Reacting with Water

Ca + 2H2O → Ca(OH)2 + H2

Overview

Calcium reacts with water to produce calcium hydroxide (limewater) and hydrogen gas. The reaction is moderately vigorous, producing a milky suspension of sparingly soluble calcium hydroxide. Calcium sinks in water (unlike sodium) and reacts at the bottom of the vessel.

Participants

Role Substance Coefficient State
Reactant Calcium Ca 1 (s)
Reactant Water H₂O 2 (l)
Product Calcium Hydroxide Ca(OH)₂ 1 (s)
Product Hydrogen H 1 (g)

Everyday Example

The milky appearance of hard water deposits and limescale is related to calcium hydroxide and carbonate formation from calcium's reactions in water.

Industrial Importance

Understanding calcium-water reactions is important for water hardness treatment, concrete chemistry, and calcium hydroxide production for industrial applications.

Properties

Type
Single Replacement
Reversible
No
Energy
Exothermic
ΔH
-635.1 kJ/mol

Related Reactions

Aluminum Reacting with Hydrochloric Acid Aluminum Reacting with Iron(III) Oxide (Thermite) Aluminum Reducing Chromium Oxide (Aluminothermic) Carbon Reducing Iron Oxide in Blast Furnace Chlorine Displacing Bromine from Sodium Bromide Chlorine Displacing Iodine from Potassium Iodide Copper Displacing Silver from Silver Nitrate Fluorine Displacing Chlorine from Sodium Chloride Hydrogen Reducing Copper Oxide Iron Displacing Copper from Copper Sulfate

Frequently Asked Questions

What is the equation for Calcium Reacting with Water?
The balanced equation is: Ca + 2H₂O → Ca(OH)₂ + H₂.
What type of reaction is Calcium Reacting with Water?
Calcium Reacting with Water is a single replacement reaction.
Is Calcium Reacting with Water exothermic or endothermic?
Calcium Reacting with Water is exothermic (releases energy). The enthalpy change (ΔH) is -635.1 kJ/mol.