Chapter 6
Solutions, Acids, and Bases
• Chapter Preview:
• 6.1) Solutions and Other
Mixtures:
– Heterogeneous Mixtures
– Homogeneous Mixtures:
• 6.2) Dissolving and Solubility:
– The Dissolving Process
– Water: A Common Solvent
– Concentration
• 6.3) Acids, Bases, and pH:
– What are Acids?
– What are Bases?
– How Acidic Is and Acid?
– Neutralization Reaction
• 6.4) Acids and Bases In the Home:
– Cleaning Products
– Other Household Acids and
Bases
Section 6.1: Solutions and Other Mixtures
• Objectives: distinguish between
homogeneous mixtures and
heterogeneous mixtures.
• Compare and contrast the
properties of solutions, colloids,
and suspensions.
• Identify ways to separate
different kinds of mixtures.
Heterogeneous Mixtures:
• A heterogeneous mixture, such as
fruit salad is not the same
throughout.
• Suspension: a mixture that looks
uniform when stirred or shaken
that separate into different layers
when it is no longer agitated.
Particles size of about 1000 nm.
• Colloid: a mixture of very tiny
particles of pure substances that
are dispersed in another
substance but do not settle out of
the substance. Particles size from
1 to 100 nm in diameter.
Heterogeneous Liquid – Liquid Mixtures:
• When oil is mixed with vinegar to
make salad dressing, two layers
form.
• Immiscible: when two liquid
don’t mix.
• Emulsion: any mixture of
immiscible liquids in which the
liquids are spread throughout one
another.
Homogeneous Mixtures:
• Homogeneous Mixtures not only
look uniform, they are uniform.
– For example: salt water, kool –aid,
and lemonade, etc.
Solutions are homogeneous mixtures:
• Solution: a homogeneous
mixture of two or more
substances uniformly spread
throughout a single phase.
• Solute: the substance that
dissolves in a solution.
• Solvent : the substance that
dissolves the solute to make a
solution.
• Miscible liquids mix to form
solutions.
• One way to separate miscible
liquids is by a process called
distillation. For example water
mixes with isopropanol to make a
solution of rubbing alcohol.
Section 6.1 Summary Report
• A heterogeneous mixture is a
nonuniform blend of two or more
substances.
• The particles in a suspension
soon settle out of the mixture.
• The dispersed particles in a
colloid are smaller and do not
settle out.
• An emulsion is a colloid in which
liquids that normally do not mix
are spread throughout one
another.
• A homogeneous mixture, or
solution, is a uniform blend of
two or more substances.
• In a solution, the solute is
dissolved in the solvent.
Section 6.2
Dissolving and Solubility
• Describe how a substance
dissolves in of its solubility,
molecular motion, and solutesolvent interactions.
• Identify several factors that affect
the rte at which a substance
dissolves.
• Relate the structure of water to
its ability to dissolve many
different substances.
• Distinguish between saturated,
unsaturated, and supersaturated
solutions.
The Dissolving Process
• According to the kinetic theory,
the water molecules in each glass
of tea are always moving.
• Some moving water molecules
collide with sugar crystals.
• When this happens, energy is
transferred to the sugar
molecules at the surface of the
crystal.
• Solutes with a larger surface area dissolve faster.
• Stirring or shaking a solution helps the solute dissolve faster.
• Solutes dissolve faster when the solvent is hot.
• Not every substance dissolves.
– Soluble in water
– Insoluble in water
Water: A Common Solvent
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Two-thirds of Earth’s surface is water.
The liquids you drink are mostly water.
Water is colorless and tasteless.
Water is sometimes called the universal solvent.
Characteristics of Water:
• The structure of water helps it dissolve charged particles:
• “Like dissolves like”:
– Water can dissolve many substances, but there are many others it
can’t dissolve.
– For example, olive oil doesn’t dissolve in water, and neither does
gasoline. That because its components are non-polar, meaning their
molecules do not have partial charges on opposite ends.
Concentration
• You can make a solution by dissolving sodium acetate in water. But how
much sodium acetate do you need to add?
• Concentration: the quantity of solute dissolved in a given quantity of
solution.
Types of Solutions:
Unsaturated Solution: a solution that is able to dissolve more.
Saturated solution: a solution that cannot dissolve any more solute at the
given condition.
• Supersaturated solution: a solution holding more dissolved solute than is
specified by its solubility at a given temperature.
Section 6.2 Summary Report
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The larger the surface area a solute has, the faster it will dissolve.
Stirring or shaking the solution dissolves solutes faster.
Heating a solvent also dissolves solutes faster.
So many substances are soluble in water that it is sometimes called the
universal solvent.
• An unsaturated solution can dissolve more solute.
• A saturated solution cannot dissolve any more solute.
• A solute’s solubility is exceeded in a supersaturated solution.
Section 6.3
Acids, Bases, and pH
• Objectives:
– Compare and contrast acids and bases.
– Relate the pH of a solution to the concentration and strength of
dissolved acid or base.
– Identify the products of neutralization reactions.
What are Acids?
• Acid: a substance that donates hydrogen ions, H+, to form hydronium ions,
H3O+, when dissolved in water.
– Sour
– Conduct electricity and heat
– Turn litmus paper from blue to red
– Examples; lemon, lime, dill pickles, etc.
What are Bases?
• Base: a substance that either contains hydroxide ions, OH-, or reacts with
water to form hydroxide ions.
• Bitter
• Conductors of electricity and heat.
• Turn litmus paper from red to blue.
How Acidic Is an Acid and How Basic Is a Base?
• pH: a measure of the hydronium ion concentration in a solution.
• The pH values correspond to the concentration of hydronium ions.
• Small differences in pH values mean larger differences in hydronium ion
concentration.
Neutralization Reactions:
• Neutralization reaction: a reaction in which hydronium ions from an acid
and hydroxide ions from a base react to produce water molecules.
– Note: strong acids and bases react to form water and a salt.
– Note: some acid-base reactions do not result in neutral solutions.
Section 6.3 Summary Report
• Acids are sour, corrosive
substances that form hydronium
ions when dissolved in water.
• Bases are bitter, slippery
substances that either contain
hydroxide ions or form them
when dissolved in water.
• Indicators are substances that
change color depending on
whether a solution is acidic,
basic, or neutral.
• Neutral solutions have a pH of 7,
acidic solutions have a pH of less
that 7, and basic solutions have a
pH of greater than 7.
• A neutralization reaction occurs
when hydronium ions and
hydroxide ions react to form
water molecules.