The document discusses acids, bases, and pH. It defines ions as charged atoms or molecules, and explains that acids donate H+ ions to solutions while bases remove H+ ions, thereby making the solution more alkaline. The pH scale measures how acidic or basic a solution is on a scale from 0-14. Buffers help maintain pH levels in living cells by accepting or donating H+ ions when their levels fluctuate.

1. ACID BASES AND PH
CHEMICAL BASESOF LIFE

2. What is an ion?
•An ion is a charged atom or
molecule. It is charged
because the number of
electrons do not equal the
number of protons in the
atom or molecule.
When an atom is attracted
to another atom because it
has an unequal number of
electrons and protons, the
atom is called an ION. If the
atom has more electrons
than protons, it is a
negative ion, or ANION. If it
has more protons than
electrons,it is a positive ion
CATION.
An atom can acquire a
positive charge or a negative
charge depending on the
number of electrons in an
atom is greater or less then
the number of protons in the
atom.

3. ACID AND BASE CONCEPTS
•In Aqueous solutions, small percentage of the water
molecules themselves break apart into ions. The ions
formed are positively charged hydrogen ions (H+) and
negatively charged hydroxide ion (OH-).
•For the chemical processes of life to work correctly, the
right balance of H+ ions and OH- ions is critical.
•Some chemical compounds contribute additonial H+ ions to
an aqueous solution while others remove H+ ion from it.
Hydroxide ion -
Hydrogen ion +
WATER
MOLECULE

4. ACID AND BASE CONCEPTS

5. Acid (acids)
•A compound that donates H+ ions to a
solutions is called an ACID (Hydrovhloric acid
HCl in aqueous solution brakes completely in
H+ and Cl-)

6. BASE (BASES)
•A compound that removes H+ ions From an
aqueous solution is called a BASE.
•Some bases (sodium hydroxide NaOH), do this
by adding OH- ions, which then combine with
H+ ions and form water molecules

8. Ph scale
• Describes how acidic or basic a solution is.
• Scale ranges from 0 (most acidic)
• to 14 (most basic or Alkaline)
• Lemon juice: ph 2
• Grape juice : ph 3 ten times more H+
• Neurtral : pure water or aqueous solutions that have an equal amounts of
H+ and OH- ions.
• pH 7 are neither acidic nor basic.
• pH of the solution inside most living cells is close to 7

9. Buffers
•Molecules in cells are very sensitive to
concentrations of H+ and OH-
•The slight change in pH can be harmful to
organisms.
•Many biological fluids contain BUFFERS:
•Substances that cause a solution to resist changes
in pH.
•A buffer works by ACCEPTING H+ ions when their
levels rise, and DONATING H+ ions when the
levels fall, thereby maintaining a fairly constant
pH in the solution.
•

10. AN ENVIRONMENT FIT FOR LIFE
•The abundance of the liquid water: water is needed
for life.
•Planets location in the solar system:far enough so it
recives a moderate quantity of energy but not so
far away that temperatures are too cold
•Ozone gas shields the planet´s surface from
harmful radiation
•Availability of essential elements for life: soil, rocks
and atmosphere.

11. Ph acid base videos
• https://www.youtube.com/watch?v=RF40cI2O16U
• Cabache experiment