1. Notes # 2
acids, bases and ph

2. pH: a measure of how acidic or basic a substance is.
pH: solutions can be classified as an acid, a base or neutral based on their pH.
pH is a physical property of matter.
Physical properties are properties of solutions that can be observed without causing a chemical change.

3. Indicators are used to determine the pH of a solution.
Determining pH
Indicators are used to determine the pH of a solution.
pH range in a solution is between 0 and 14
When acids and bases react with each other they form neutral solutions.
This is called a neutralization reaction.

4. Acids/Acidic solutions
Acids can be identified by their sour taste, for example lemon juice
Reaction to metals, such as zinc and acid gives of gas
Reaction with bases to form neutral pH solutions. Example: vinegar and baking soda
Acids have a pH of less than 7.0
The lower the number the more acidic it is

5. Formulas for acids usually have Hydrogen as the first element.
Examples:
HCl: Hydrochloric acid or stomach acid
H2 SO4: Sulfuric acid, an industrial acid

6. Bases have a bitter taste, such as unsweetened chocolate
Base/Basic solutions
Bases have a bitter taste, such as unsweetened chocolate
They have a slippery feel like dish soap
They react with acids to from neutral solutions, like Tums to settle an upset stomach
Bases have a pH greater than 7.0
The closer to 14 the more basic

7. Formulas for Bases can be recognized by an OH ending. Examples
NaOH: Sodium Hydroxide, drain cleaner
Ca(OH)2: Calcium Hydroxide, lime fertilizer

8. Neutral/neutral solutions
Neutral solutions are neither an acid or a base
Neutral solutions have a pH of 7.0
Pure water is a neutral solution

9. pH of common substances

10. Blue litmus paper turns red in an acid
Indicators
Litmus paper: has special dye in it that changes color when in an acid or base
Blue litmus paper turns red in an acid
Red litmus paper turns blue in a base

11. Litmus paper: blue in base, red in acid

12. Phenolphthalein: is used to test for the presence of a base
Indicators
Phenolphthalein: is used to test for the presence of a base
It is colorless by itself and turns magenta in a base, and stays colorless in acidic or neutral solutions

13. Phenolphthalein: turns bright pink in a base

14. pH paper: has a range of colors depending on the pH of the solution
Indicator
pH paper: has a range of colors depending on the pH of the solution
The color of the paper is compared to the chart to determine pH

15. SAFETY
DON’T TOUCH OR TASTE LABORATORY CHEMICALS UNLESS YOU HAVE BEEN TOLD THAT IT IS SAFE TO DO SO!