Given reaction represents dissociation of bromine gas to form bromine atoms
Br2(g) ↔ 2Br(g)
The enthalpy of the above reaction is given as:
ΔH = ∑n(products)Δ - ∑n(reactants)Δ
where n = number of moles
Δ= enthalpy of formation
ΔH = [2*ΔH(Br(g)) - ΔH(Br2(g))] = 2*111.9 - 30.9 = 192.9 kJ/mol
Thus, enthalpy of dissociation is the bond energy of Br-Br = 192.9 kJ/mol
Answer: Cesium chloride dissolves in pure water has > 0.
Explanation:
Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.
is positive when randomness increases and
is negative when randomness decreases.
a)
As 2 moles of gas are converting to 1 mole of gas and 1 mole of liquid, the randomness decreases and hence is negative.
b)
As gas molecules are converting into aqueous and liquid form, the randomness decreases and hence is negative.
c) lithium fluoride forms from its elements:
As elements are combining to form a compound, the randomness decreases and hence is negative.
d) Cesium chloride dissolves in pure water :
As compound is dissociating into ions, the randomness increases and hence is positive.