Q1
di)Lattice energy is the enthalpy change when 1 mole of ionic
compound is formed from its gaseous ions
dii) mg2+ (g) + 2cl- (g)  mgcl2 (s)
ei) mgcl2 & nacl, mg2+ has a higher charge density compared
to na+ so it would have stronger electrostatic forces between
them and the lattice energy of mgcl2 would be more
eii) mgcl2 & cacl2, mg2+ is the smaller ion compared to ca2+
so the effect of the electrostatic force would be less spread
out and lattice energy of mgcl2 would be more
f) (-411) – (107+122+494-349)
= -785
Q2.
Ai) it is an endothermic reaction and needs high activation
energy
Aii) mgco3 and caco3, since mg2+ has a smaller ion size so it
can polarize co3 more easily, requiring lesser temperature
Q4.
a) Solubility of sulfates decreases down the group due to
the lattice energy and hydration energy required
decreasing. Since hydration decreases more than the
lattice energy the enthalpy of solution becomes more
endothermic
Bii) sr(oh)2 is more soluble in water
Bii) since delta h is negative
Q6
ai) when 1 mole of ionic compound is formed from its
gaseous ions
Aii) mg2+ + 2O-  MgO
Q7
Ai) when 1 mole of specified gaseous ions are dissolved
in water to form a dilute solution
Aii) mg2+(s) + aq  mg2+(aq)
Aiii) mg2+ has a smaller ion size and a higher charge
density than ca2+
Aiv) o2- reacts with water to form OH- molecules
ci) 641-801 = -160
cii) (1890-2526-160) / 2 = -398
cii) mgso4 is more soluble than baso4 since solubility
decreases down the group. Enthalpy of solution of
mgso4 is more endothermic than baso4. Mg2+ is the
smaller ion compared to ba2+ hence a smaller lattice
energy
Q8
A) 2Na+(g) + O2-(g)  Na2O(g)
Bi) 1: 2na(g) 2: O(g)
Bii) 1- IE1
2- EA1&2
3- lattice energy
4- formation
di) MgO and NaO, mgo has a higher lattice energy
than nao due to the higher charge density
Q9
c) Thermal stabilities of carbonates decreases down the
group due to the larger ion sizes it is less polarizing
Q10
Solubility of group 2 sulfates decreases down the group the
hydration energy decreases dtg and so the enthalpy of
solution becomes more exothermic
Q11
a) Ag+ (g) + Br- (g)  AgBr(s)
b) Agcl would have a higher lattice energy than agbr since
the ion size is smaller
Q12
Thermal stabilities of nitrates dtg decreases because the ion
sizes increase and charge density increases, it requires more
temperature to heat dtg
Q13
Soulbility of sulfates decreasws dtg since lattice energy
decreases but hydration energy decreases more
Q14
Thermal stabilites of carbonates increases since ion size
increases and the charge density decreases making it easier
to polarize the cation dtg
Q15
a) Ca2+ + 2Cl-  Cacl2(s)
b) I) cacl2 is lesser since f- is smaller than clii) cacl2 is lesser since s-2 has more charge density than
clQ16
Solubilities of sulfates decreases since lattice and hydration
values decrease but hydration decreases more