1. pH

2. Acids, Bases, and pH Water molecules can react to form ions.
H2O  H OH-
(water)  (hydrogen ion) (hydroxide ion)
Water is neutral because the number of H+ is equal to the number of OH-.

3. pH Scale
The pH scale indicates the concentration of H+ ions in a solution.

4. pH Acid- substance with a pH below 7 Base- substance with a pH above 7
The lower the number, the stronger the acid
Base- substance with a pH above 7
The higher the number the stronger the base
Neutral- pH around 7

6. Scale Each step on the pH scale represents a factor of 10. Buffers
If something has a pH of 4, then there are 10 times the number of H+ as something with a pH of 5.
Buffers
Used to control pH levels for homeostasis
Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

7. Scientific Notation Giga G 1,000,000,000 1 x 109 Mega M 1,000,000
Prefix
Abbreviation
Factor of base unit
Scientific Notation
Giga G
1,000,000,000
1 x 109
Mega M
1,000,000
1 x 106
Nano n
1 x 10-9
Pico p
1 x 10-12

8. Problem
A child who measures one meter in height is 10,000 times larger than the typical animal cell. Which of these is the size of the animal cell in meters?
A. 1 x 10-2 m
B. 1 x 10-3 m
C. 1 x 10-4 m
D. 1 x 10-6 m

9. Solution
The child who is one meter tall is bigger than the animal cell, therefore to find the size of the animal cell, divide 1 by To make a whole number, more the decimal point 4 places to the right. “4” will be the exponent for 10. Since the value (0.0001) is less than one, the exponent is negative. The correct answer is C.