Dissolving Compounds For a substance to dissolve solutesolvent attractions must overcome the attractions within both solute and solvent Example In order to dissolve ionic bonds must be broken by water ID: 475016
Download Presentation The PPT/PDF document "8.3 The Dissolving Process" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
8.3 The Dissolving ProcessSlide2
Dissolving Compounds
For
a substance to dissolve,
solute-solvent attractions must overcome the attractions within both solute and solvent. Example: In order to dissolve, ionic bonds must be broken by water. Slide3
Dissolving Ionic
C
ompounds
When ionic compounds are dissolved, water molecules reorient themselves such that their poles are oriented around oppositely charged ions.
I
onic
solutions conduct
electricity – Free ions in solution Slide4
Dissolving Ionic Compounds
Hydration:
the
process in which ions are surrounded by water molecules Dissociation: The
process in which ions separate from ionic crystals, becoming individual
ions.
NaCl
(s)
Na
+
(
aq
) +
Cl
-
(
aq
)
Na
2
CO
3
(s)
2Na
+
(
aq
) + CO
3
2-
(
aq
)
Only ionic compounds undergo dissociation
Water is not included as it does not undergo a chemical changeSlide5
Writing Dissociation Equations
Write
dissociation equations for:
magnesium chloridepotassium phosphate
aluminum oxide
ammonium
sulphateSlide6
Dissolving Molecular Compounds
Solubility of molecular compounds varies
glucose(C
6H12
O
6
) and ethanol (C
2
H
5
OH) form solutions, while oil does not.
Miscible:
liquids that can mix
to form a
solution
i
e
: alcohol and water
Immiscible:
liquids that can not mix
to form a
solution
i
e
: oil and waterSlide7
Dissolving Molecular Compounds
Water
and ethanol both contain O-H bonds.
Both can form hydrogen bonds and form them with each other when they are mixed. Attractive forced allow water and ethanol to mix to form an aqueous solution.Slide8
Ionic and
polar
compounds dissolve
in polar solvents due to solute-solvent attractions. Non-polar solutes do not dissolve in polar solvents – weak solute-solvent attractions
Non
-polar solutes
do dissolve
in non-polar solvents.
Oil and water do
not mix!
Like Dissolves LikeSlide9
Surfactants
Polar and non-polar compounds can be encouraged to mix using
surfactants
– aka detergents.Detergents contain a long non-polar hydrocarbon chain attached to a polar headThe hydrocarbon chain latches onto non-polar compounds while the charged is attracted to water molecules Slide10
Homework
Read
: Section 8.3
Questions
: Page 389 # 6, 8, 9, 10, 15,