Resolving Dissolving p. 119. Resolving Dissolving Create a new title/thread “Resolving Dissolving” and date:11/19/13 Learning Target: I can explain why.
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Slide 1
Resolving Dissolving p. 119
Slide 2
Resolving Dissolving Create a new title/thread Resolving
Dissolving and date:11/19/13 Learning Target: I can explain why
some substances dissolve in water and others do not. Update your
Table of Contents!
Slide 3
Resolving Dissolving Read the intro on p. 119 Put your work
under Process & Procedure p. 119
Slide 4
Resolving Dissolving Process and Procedures 1. Read Solvation
Process (p. 120-122) Work within your table group to answer any of
your questions in your T- table. Create a T-Table to take notes on
the reading assignment Fact or Idea on one side Questions I have
about the fact or idea on the other side Make sure to update your
vocab section with new vocabulary words that you find in the
reading 2. Using your knowledge of covalent and polar molecules
from the reading, draw a series of sketches that show why water
does not dissolve paraffin. Include + and - symbols where
appropriate. Explain each sketch with a caption. 3. Read the
Passage Other Polar Covalent Molecules: Repeat 1-2. Use sketches to
explain why molecules such as sugar are soluble in water
Slide 5
Resolving Dissolving All matter demonstrates electrical
properties Means that all matter is made up of plus and minus
charges But not all matter demonstrates electrical properties in
the same way! Why do certain substances dissolve in water? Because
they have similar electrical properties
Slide 6
Resolving Dissolving From particular properties, the salts
(hard crystalline solids with high melting points and high
conductivity in solution) dissolve in water. They dissolve in water
because they have similar electrical properties. Oils and wax have
low melting points and do not conduct electricity. They do not
dissolve in water because they have different electrical
properties.
Slide 7
Resolving Dissolving Ions are charged particles. Solids made of
ions are called ionic compounds.
Slide 8
Resolving Dissolving Solid sodium chloride is made up of ions.
Positive Sodium Ions (Na + ) and negative Cloride Ions (Cl - )
Because the ions have opposite charges, they are attracted to each
other. This attraction keeps them locked in place the structure is
called a crystal lattice. Since the ions in a solid are not free to
move around, a solid ionic compound cannot conduct
electricity.
Slide 9
Resolving Dissolving Ionic compounds can dissolve in water
because water is polar Water has a dipole (a positive end and a
negative end in the same molecule). The negative end of a water
molecule will attract Na + The positive end of a water molecule
will attract Cl - This attraction is enough to pull the ions free
from the crystal lattice.
Slide 10
Resolving Dissolving Once the ions are free of the crystal
lattice, they are surrounded by water molecules. The process of
water interacting with ions and dissolving an ionic compound is
called solvation. The ions (charged particles) can move freely,
which is why ionic compounds can conduct electricity in
solution
Slide 11
Resolving Dissolving General rule: substances with similar
electrical properties to water molecules will dissolve in water.
Like dissolves like
Slide 12
Resolving Dissolving Why doesnt baby oil and wax dissolve in
water? Because they have different electrical properties than
water! There are no dipoles in wax or baby oil (no sections of plus
and minus charge). These are non-polar molecules. Baby oil and wax
are covalent molecules The plus and minus charges are equally
distributed over the whole molecule, so there are no dipoles.
Resolving Dissolving P&P #2: Why does paraffin (wax) NOT
dissolve in water?
Slide 15
Resolving Dissolving Read Other Polar Covalent Molecules p.123-
124 Take notes Remember to include a summary at the end! Do R&C
#1-3 on page 124 - 125!
Slide 16
Other Polar Covalent Molecules Dipoles are the result of
differences in the plus- minus nature of atoms. The strength of the
dipole is determined by the electrical properties of the atoms that
make up the molecule. Molecules that contain dipoles can attract
each other. The strength of attraction depends on the strength of
the dipoles involved.
Slide 17
Other Polar Covalent Molecules Molecules with dipoles interact
because of their plus and minus parts. Molecules with dipoles will
dissolve in each other (because their plus and minus parts
interact).
Slide 18
Other Polar Covalent Molecules Sugar dissolves in water because
parts of the molecule have a dipole.
Slide 19
Other Polar Covalent Molecules Most organic compounds are made
of carbon rings. They contain dipoles (of different strengths)
because there are stronger atoms bonded to the carbon. The dipoles
make it so that these organic compounds are soluble in water.