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Solutions and
Properties of
Water
Do Now
Is chlorine a reactive element?
Explain why or why not.
Go Over Assignment
• Practice problems #2, 3, & 9 (p. 14)
• Practice Problems #9-12 (p. 17-23)
• 1.2 Questions: Pg. 23-24 #1-5
• Diagrams of Atoms Summative Assignment–Due
Monday, February 8th.
The Plan
• Learn about chemical change, solutions, solvents
& solutes.
• Discuss why water is an excellent solvent.
• I can explain how dissolving substances in water
is often required for chemical reactions.
Chemical Change
• The way to tell if a chemical change is occurring
or has occurred is if there is a new substance
produced, accompanied by a change in colour,
odour, state, or energy.
• Changes in state usually involve formation of gas
or solid.
Chemical Change
• Chemical changes show that bonds between
atoms in the original substance have been
broken and new bonds have been formed to
create new substances.
• Weird Chem RXN
Solutions
• Often, substances are dissolved in water in order
for chemical changes and reactions to occur.
When matter is dissolved in water this forms
something called an aqueous solution.
• Examples: Sea water, urine, crystal light
Alka Seltzer in Stomach
Reaction
• NaHCO3 + HCl => NaCl + CO2 + H20
Solutions
• Solutions are homogeneous mixtures of
substances composed of at least one solvent
and one solute
• Solvents are the substances in which the
solutes dissolve.
• Water is the most common solvent and
forms aqueous solutions.
• Solutes are the substances dissolving into
the solute.
• (e.g. in salt water, salt is the solute and
water is the solvent.)
Crystal Light
• What is our solvent?
• What is our solute?
Structure of Water
• Triatomic molecule
• Meaning it has 3
atoms
• Held together by
covalent bonds
• Oxygen and the 2
hydrogens share the
electrons
Structure of Water
• Oxygen has a stronger pull on the electron than
hydrogen.
• it is considered to be a polar molecule, because
one end (the oxygen) has a more negative charge
than the other end (the hydrogen).
• Polarity DEMO
Polarity of Water
• polar molecules attract one
another  water molecules
tend to “stick together”
more strongly than other
molecular compounds that
are non-polar
• polar substances act as good
solutes for other polar
molecules and for all ionic
compounds.
Aqueous Solutions
• Aqueous solutions are by far the most common and
versatile type of solutions
• All aqueous solutions are clear or transparent
Solvation
• The process of a solute dissolving in a solvent
• Solute is added to solvent  solvent particles attract
solute particles  bonds holding solute together break
down  solute becomes surrounded by solvent
molecules
• if the attraction between particles of the solute is
stronger than those with water, the particles of the
solute will not solvate very much (e.g. oil in water)
Assignment
• Read pgs. 24-31
• 1.3 Questions pg. 33 #1,2,4, 5