Transcript 604 SOLLUBILITY TABLE G

NH3 has a
solubility of 60g at
180C in 100.0mLof
water.
KNO3 has a
solubility of 60g at
380C in 100.0mLof
water.
HCl has a solubility
of 60g at 480C in
100.0mLof water.
KClO3 has a
solubility of
60g at
100oC in
100.0g
water.
NH4Cl has a
solubility of
60g at 66oC
in 100.0g
water.
NH3 has a
solubility of 60g at
180C in 100.0mLof
water.
KNO3 has a
solubility of 60g at
380C in 100.0mLof
water.
HCl has a solubility
of 60g at 480C in
100.0mLof water.
KClO3 has a
solubility of
60g at
100oC in
100.0g
water.
NH4Cl has a
solubility of
60g at 66oC
in 100.0g
water.
The
solubility
of NaNO3 at
520C is
120g in
100mL of
water.
The
solubility
of NaNO3 at
27oC is
about 94g
in 100mL
of water.
As you see from
the graph the
solubility of
NaNO3
INCREASES as
temperature
INCREASES. This
is due to the fact
that the
dissolving of this
salt is
ENDOTHERMIC,
energy
absorbing, q is +.
The solubility of NH3
DECREASES as the
temperature
INCREASES, Therefore
the dissolving of
ammonia is
EXOTHERMIC – it
cannot give off heat at
higher temperatures
which hinders
dissolving. The heat
transfer is negative (-q)
for this reaction. This is
typical of gasses which
dissolve poorly at higher
temps.
At 10oC NH3
has a
solubility of
70 grams of
NH3 in 100
grams of
water.
At 70oC NH3
has a
solubility of
19 grams of
NH3 in 100
grams of
water.
U DO IT NOW
1/29/07
1. What will occur if NaNO3 is cooled from
52oC to 27oC?
2. Which is the most soluble substance at
37oC, which is the least soluble.
3. Identify the gases in the table.
4. What will occur as the temp. of NH3(aq) in
solution is increased from 10oC to 70oC?
The
solubility
of NaNO3 at
520C
HOLDS
120g in
100mL of
water.
The
solubility
of NaNO3 at
27oC
HOLDS
about 94g
in 100mL
of water.
As the temperature
drops from 52oC to
27oC the solubility
drops from 120g to 94g.
The difference of 26g
will precipitate out as a
solid on the bottom of
the vessel. The 120g
that is saturated at 52oC
is supersaturated at
27oC. At 27oC only 94 g
can dissolve, 26g of the
120g must precipitate to
reach 94g.
(520C,120g)
(270C, 94g)
Energy is needed to
break the electrostatic
attractions of the
lattice, (lattice energy)
At 52oC 120g of
NaNO3 will dissolve,
the solution has
120g in 100g water.
COOLING
CAUSES
The electrostatic
attractions to begin
to form the ionic
crystal lattice.
A
precipitate
forms.
The solution that could
carry 120g at 52oC cannot
hold that much at lower
tamps precipitate will form
as it cools.