Solutions. What is a solution? A solution is a mixture that has the same composition, color, density...
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Chapter 22 Solutions
Solutions. What is a solution? A solution is a mixture that has the same composition, color, density and even taste throughout The most common solutions
What is a solution? A solution is a mixture that has the same
composition, color, density and even taste throughout The most
common solutions are liquids and have water in them, but not all
are To describe a solution, you might say that one substance is
dissolved in another
Slide 3
Parts of a solution The substance being dissolved is the
solute, and it is always in lower amounts that the solvent The
solvent is the substance that does the dissolving and is always in
higher amounts than the solute Water is known as the Universal
Solvent because it can dissolve many things
Slide 4
Non liquid Solutions Solutions can be solid, like bronze, which
is a mixture of both copper and tin. Brass is a mixture of copper
and zinc. Solid solutions are known as alloys Air is a gaseous
solution that is a mixture of Nitrogen, oxygen, carbon dioxide,
hydrogen and others.
Slide 5
Identify the solvent and solute in each Kool Aid Ocean water
Bronze Air Carbonated soft drink
Slide 6
Water is Polar Water is a special molecule that can dissolve
just about everything The trick is, like dissolves like Water is a
polar liquid, so it can dissolve polar solids such as salt
Something is considered polar if it has a positive area and a
negative area in the same molecule
Slide 7
Polar Molecules Water Table Salt and Water
Slide 8
How does sugar dissolve in water Step 1: Water clusters around
sugar molecules, negative ends attracted to positive Step 2: Water
molecules pull sugar molecules into solution Step 3: Water and
sugar molecules mix evenly, forming a solution
Slide 9
More Dissolving Gases can dissolve in liquids Liquids can also
dissolve in liquids Making solid solutions, or alloys is more
complicated, you must melt the solids down and mix them so they
will remain mixed when cooled
Slide 10
Rate of Dissolving When one thing dissolves in another, it does
so at a constant rate You can increase the dissolving rate by doing
three things 1. Stirring- brings more solvent into contact with
solute 2. Decreasing crystal size (grinding)- gives solvent more
surface area to dissolve 3. Increase temperature- makes particles
move faster and mix easily
Slide 11
Slide 12
Solubility and Concentration How much can dissolve? Solubility
is the maximum amount of solute that can be dissolved in a solvent
at a certain temperature Concentration depends on how much solute
is dissolved in the solvent A solution with more solute than
another in the solvent is considered more concentrated Example
orange drink is 10 % juice, where orange juice is 100 % juice the
juice is more concentrated in one than the other
Slide 13
Saturated vs Unsaturated Solutions A saturated solution is one
that holds all the solute that it can at a certain temperature. In
an unsaturated solution, more solute can be dissolved in the
solvent at a certain temperature
Slide 14
Solubility Curves You can use these to determine how much of a
solute can dissolve in a given solvent at a certain
temperature
Slide 15
Supersaturated Solutions Unstable solution that have more
solute dissolved in the solvent than they should You can
supersaturate a solution by heating it, forcing more solute to
dissolve, then letting it cool As it cools, some of the solute
falls out of solution You can make rock candy using a
supersaturated solution of sugar and water
Slide 16
Solubility of Gases You can increase the amount of a gas
dissolving in a liquid by INCREASING the pressure or DECREASING the
temperature More carbon dioxide gas is dissolved in a cold soft
drink than a warm one, thats why sodas get flat as they warm
up
Slide 17
Particles in Solution Pure water is a poor conductor of
electricity. In order for water to conduct electricity well, you
have to add ions to it. Solutions of ions that conduct electricity
well are called electrolytes
Slide 18
Effects of Solute Particles Adding antifreeze to the water in
your car radiator both lower the freezing point of the water AND
raise the boiling point of water Meaning, that with the antifreeze,
the water in your radiator wont freeze or boil as easily Some
animals such as polar fish and caribou have a natural antifreeze in
their bodies that keep them from freezing in cold temperatures
Slide 19
When Water Wont Work Water cannot dissolve all substances. If a
substance is non-polar, meaning it has even charges all the way
through and no negative and positive ends, the water cannot
dissolve it Some substances are both polar and non-polar because
part of the molecule is charged, and the other part is not. Ethanol
is an example.
Slide 20
Nonpolar Solvents Goo gone, lighter fluid, dry cleaning
solution are all examples of nonpolar solvents and can dissolve
things that water cant. Nonpolar solvents are often toxic and
flammable They can produce harmful vapor
Slide 21
The Chemistry of Soap Non polar ends of soap attach to dirt and
oil and dissolve it Polar ends of soap mix with water and all is
washed away Soap works because it is BOTH Polar and Non-polar
Slide 22
Chapter 23
Slide 23
Acids Acids can be harmful or they can be safe, depending on
the specific one What they all have in common, is that in solution,
they all release H+, hydrogen, or hydronium ions into water Acids
have a sour taste Some are corrosive and can react strongly with
certain metals Acids also react with indicators (a substance used
to identify acids and bases) Litmus paper, for example, changes red
in presence of an acid
Slide 24
Common Acids Hydrochloric Acid HCl gastric juices (stomach
acid) Ascorbic Acid vitamin C Citric Acid found in citrus fruits
Carbonic Acid- carbonated drinks Sulfuric Acid battery acid
Slide 25
Bases In solutions, bases release OH- or hydroxide ions into
water Bases are the opposite of acids They are smooth and slippery
They have a bitter taste Strong bases are corrosive and can burn
Litmus paper turns blue in bases
Slide 26
Common Bases Soaps Cleaning supplies Bleach Milk of Magnesia
Alka Seltzer and Tums (antacids)
Slide 27
Ammonia is Special Ammonia is a strong base used as a cleaner
It does not form hydroxide ions in solution Do not use ammonia with
anything containing chlorine like bleach If you mix the two
together, it makes a poisonous gas that is fatal
Slide 28
Dissociation When acids and bases dissolve in water, the ions
are attracted to the water and in some cases, they are mixed
completely in the water This is called dissociation When acids
dissociate, they release H+ ions in water (hydronium) When bases
dissociate, they release OH- ions in water (hydroxide)
Slide 29
Strong and Weak Acids and Bases The strength of an acid or base
depends on the number of ions dissociated in solution A strong acid
or base has many ions in solution, dissociates completely A weak
acid or base has few ions in solution, does not dissociate
completely Ions meaning H+ for acids and OH- for bases
Slide 30
pH of Solutions pH of a solution is the measure of the
concentration of H+ ions in solution The pH scale ranges from 0 to
14 An acid has a pH below 7 A base has a pH above 7 7 is neutral,
pure water is an example You can measure pH using a pH meter or
indicator pH paper, which turns a certain color for each pH
value
Slide 31
pH Scale
Slide 32
Blood pH In order for blood to function properly, it must have
a pH between 7 and 7.8 Many enzymes cannot work outside this range
How is it that you can eat acidic foods and not change your blood
pH? Your blood contains buffers, solutions containing ions that
react with acids and bases to minimize changes in pH
Slide 33
Neutralization Antacids such as Tums or Alka Seltzer produce
what is called neutralization in your stomach This is because too
much acid can cause discomfort Neutralization is a chemical
reaction between an acid and a base which produces water Remaining
ions in a solution react to form salts
Slide 34
Salts Salts are essential for healthy life Most salts contain a
positive metal ion and an ion with a negative charge Ammonium salts
contain the ammonium ion instead of a metal