Transcript pH06 - McCarthy`s Cool Science

Assignment #
Acidic, Basic, and Neutral Solutions
Biology
Mrs. McCarthy
Saturday, April 9, 2016
I.
Acidic, Basic, and Neutral Solutions
A.
Solutions are acidic, basic, or
neutral depending on the
concentration of hydrogen ions
(H+) in the solution.
1. Acidic solutions
contain more hydrogen ions (H+)
Release hydrogen as they dissolve
HCl
H+
Cl-
Examples: grapefruit juice, vinegar,
coffee, digestive juices
2. Basic solutions
contain more hydroxide ions (OH-)
Release hydroxide ions as they dissolve
NaOH
Na+
OH-
Examples: baking soda, soap, egg whites,
bleach
2. Neutral solutions
Have an equal amount of hydrogen and
hydroxide ions
H 2O
H+
OH-
Examples: pure, distilled water
I.
Acidic, Basic, and Neutral Solutions
B. pH scale
p = potential
H = hydrogen ions
Standard scale of hydrogen ions present
in a solution
There is a 10x difference between each
number in the pH scale
Example
pH 2 is 10x stronger than pH 3
pH 3 is 10x stronger than pH 4
Therefore:
pH 2 is 100x stronger than pH 4
How many times more acidic is pH 5 than
pH 8?
1,000 times
How many times more basic is pH 11 than
pH 7?
10,000 times
Scientific notation can be used to show the
difference between numbers on the pH
scale. Scientific notation is a way to make
these numbers easier to work with. In
scientific notation, you move the decimal
place until you have a number between 1
and 10. Then you add a power of ten that
tells how many places you moved the
decimal.
Here are some examples of
scientific notation and the
numbers it represents:
Abbreviation
1.0 x 10-5
2.5 x 10-3
1.0 x 102
3.4 x 102
1.0 x 105
105
6.0 x 106
Number
.00001
.0025
100
340
100,000
100,000
6,000,000
Use scientific notation to show how many
times more acidic pH 2 is than pH 12:
2 is 10 places away from 12 on the scale
10 10 = 10000000000
OR
1 x 10 10 times more acidic
Practice:
1. Write 123,000,000,000 in scientific
notation.
2. Write 0.00000034 in scientific notation.