Transcript Describing Aqueous Solutions - New Concept: Acidity

Describing Aqueous Solutions New Concept: Acidity
Ionization of Water
→ Remember when you learned that the formula for water
is H2O? Like, if I pointed to a glass of water and asked you,
“Hey man, what is the chemical formula for that liquid?”
You'd totally say “H2O.”
→ It turns out things aren't as simple as we thought.
→ EVEN IF IT'S JUST WATER, THERE IS MORE
THAN JUST H2O IN THAT GLASS!!
Ionization of Water
→ Water is always doing this:
H2O →
+
H
+
OH
→ Likewise, Hydrogen and Hydroxide ions
are always doing this:
+
H
+
OH
→ H2O
→ There's always gunna be some H+ and OH- ions in a
solution. ACIDITY is the measure of how many of those
ions there are.
What is an ACID??
Anything that
dissolves in a solution
+
to make more H ions
is an acid!!!

What is an ACID??
Signs that indicate something is an acid...
• Produce H+ ions when dissolved in water.
• Taste sour and tart
• Corrodes metals
• Breaks down proteins.
• pH is less than 7
• Name ends in an “-ic” or “-ous”
What is a BASE??
Anything that
dissolves in a solution
to make more OH
ions is a base!!!

What is a BASE??
Signs that indicate something is a base...
• Produce OH- (hydroxide) ions when dissolved in water.
• Have a chalky or bitter taste.
• Has a slippery or soapy texture.
• Breaks down oils very effectively.
• Neutralizes an acid.
• pH is greater than 7.
Measuring Acidity of a Solution

LITMUS PAPER is used to measure the pH of a
solution. The paper turns colors depending on the
Acidity of the solution.
Orange/Red = Acidic. Lots of H+
Purple/Blue = Basic. Lots of OH-

Some people hear
the word “acid”
and think it is
automatically
something
dangerous.
Nope.
Check out these
examples of
everyday things
that are acidic
and/or basic...
Pop Quiz

Question #1: Something that is moderately acidic
probably has a pH value around what?
A. 1.5
B. 3.0
C. 7.0
D. 10
Question #2: A STRONG BASE dissolved in
some distilled water. What might the pH be?
A. 1.2
B. 7.0
C. 9
D. 14

ACIDITY OF THE ENVIRONMENT

Living things are affected by the acidity of their
environment. Most living things cannot survive
where it is super acidic or super basic.

Acidity of the soil determines which
kind of plants are able to grow there.
Most plants prefer slightly acidic soil
between pH 5.5 - 6.5.
Soil – What is
important to it.
• Texture
• Composition
• climate
What Makes Our
Soil:
• Original soil is the
process of weathering
of rocks by water erosion
(freezing and thawing of water
which makes the cracks in the rocks
and eventually breaks them down)
• Organisms – accelerate
the decomposition
• Lichen, fungi, bacteria,
mosses help break down
rocks
1 tablespoon of soil =
5 BILLION BACTERIA, FUNGI, AND VARIOUS
CREATURES
Soil
topsoil =
Mixture of decomposed rock,
living organisms, and humus
(residue of partially decayed
organisms)
Depends on size of particles:
sand (large particles)
silt (medium sized part)
clay (small sized part)
loams (mixture of three)
LOAM = best for plants
WHY IS pH
IMPORTANT
•
SOIL BACTERIA LIKE IT A BIT
ACIDIC
•
MOST NUTRIENTS (NITROGEN,
PHOSPHORUS, SULFUR) NEED
THE H+ ION TO BOND AND
“NURTURE” THE PLANT
•
WORMS LIKE IT ACIDIC