CHEM 7.3 The pH Scale Flashcards
What is pH ?
pH stands for ‘power of hydrogen’. It is used to measure how acidic or basic a solution is.
pH is a logarithmic scale meaning that one unit on the scale is equivalent to a tenfold change in concentration.
For example, pH of 3 is 10 times more acidic than a pH of 4 and a pH of 10 is 1000 times less basic than a pH of 13.
How does the pH scale measure the acidity or basicity of a solution ? Name acidic, neutral and basic materials.
The pH scale ranges in values from 0 – 14
–The pH values from 0.0-6.999999 are acidic
e.g stomach acid, black coffee
–The pH value of 7 is neutral
e.g water
–The pH values from 7.000001 to 14.0 are basic
e.g baking soda, bleach
Compare the acidity of lemon juice (pH of 2) and black coffee (pH of 5). Are these basic or acidic products ?
Lemon juice has a pH of 2. Black coffee has a pH of 5, which means
lemon juice is 3 units, or 103
(1000x) times more acidic than black coffee.
These are acids.
