# What is the enthalpy of calcium hydroxide?

## What is the enthalpy of calcium hydroxide?

Thermodynamic properties

Phase behavior
Std enthalpy change of formation, ΔfHosolid -985.2 kJ/mol
Standard molar entropy, Sosolid 83.4 J/(mol K)
Heat capacity, cp 87.5 J/(mol K)
Liquid properties

What is the KSP value for calcium hydroxide?

6.5 × 10
8 The approximate value of the Ksp for calcium hydroxide is 6.5 × 10–6, so calculate a rough value of the concentration of OH– ion, [OH–], in the saturated solution (see prelab question on WebAssign; to two significant figures).

### What is the Ka of calcium hydroxide?

Dissociation constants of some acids and bases at 25°C (for pKa values click here)
arrange the compounds in decreasing K values
Caffeine C8H10N4O2 4.10×10-04
Calcium hydroxide Ca(OH)2 3.74×10-03
Codeine C18H21O3N 1.63×10-06

Which substances has zero Gibbs free energy of formation?

Standard Gibbs free energy of formation

Species Phase (matter) ΔGf° (kJ/mol)
Fluorine Gas 0
Hydrogen
Hydrogen Gas 0
Water Liquid −237.14

#### What is calcium oxide water?

Calcium hydroxide, also called slaked lime, Ca(OH)2, is obtained by the action of water on calcium oxide. When mixed with water, a small proportion of it dissolves, forming a solution known as limewater, the rest remaining as a suspension called milk of lime.

What is the concentration of calcium hydroxide in the saturated solution?

But, don’t forget that it contains hydroxides ions, which automatically makes it a strong base! In fact, the pH of a saturated calcium hydroxide solution is about 12.4. Thus we can classify a saturated solution of calcium hydroxide as a dilute solution of a strong base.

## How does temperature affect solubility of calcium hydroxide?

The solubility of calcium hydroxide decreases with increasing temperatures. This principle states: If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established.

What is the Gibbs energy change for calcium chloride?

For a solution to form, the Gibbs energy change must be negative for dissolving. When calcium chloride dissolves in water, \\ (ΔH\\) is negative and \\ (ΔS\\) is positive, resulting in a large negative \\ (ΔG\\) and a very high solubility (595 g/L).

### What is the Gibbs free energy of a compound?

The standard Gibbs free energy of formation of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).

How is the apparent equilibrium constant of calcium hydroxide determined?

The molar solubility of sparingly soluble calcium hydroxide in water at room temperature and in boiling water is easily determined by titration of filtered saturated solutions with standardized hydrochloric acid solution. The apparent equilibrium constant, Ksp, can be calculated from the molar solubility of calcium hydroxide: Ksp = [Ca2+] [OH-]2.

#### How is the K sp of calcium hydroxide determined?

Using these titration dat a, the K sp and ΔG 0 for the dissolution of calcium hydroxide is determined. ΔG 0, ΔS 0 and ΔH 0 for the reaction are determined from the temperature dependence. ignoring ion pair formation. The equilibrium concentration of OH – is large enough to allow its