pH

Ever wonder if there’s an opposite to acids? Well they are called Alkalines or Bases and knowing how to identify them can save your life!

PROPERTIES OF ACIDS AND BASES
ACIDS
  • Acids taste sour
  • Acids burn or sting to the touch
  • Examples:
    • Tomatoes
    • Vinegar
    • Stomach Acid
Lemon juice tastes sour, burns to the touch and has pH of 2-3.
BASES aka ALKALINE
  • Bases taste bitter
  • Bases feel slippery or slimy
  • Examples:
    • Bleach
    • Ammonia
    • Soaps
Soap is slippery, tastes bitter and has a pH of 8-10.
ACIDS HAVE LOTS OF HYDROGEN
  • Acidic substances have a pH of 0-6.9
    • In water, acids release Hydrogen particles
  • Stronger acids have more hydrogen particles and lower pH.
More Hydrogen makes a stronger Acid.
BASES HAVE LOTS OF HYDROXIDE
  • Alkaline substances have a pH of 7.1-14
    • In water, bases release Hydroxide particles
  • Stronger bases have more hydroxide particles and a higher pH.
More Hydroxide makes a stronger Base.
WHAT IS THE PH SCALE?

pH is a chemical property that denotes the amount of free hydrogen or hydroxide particles a substance has.

  • the pH scale is used to describe how acidic or alkaline substances are:
    • Acids have a pH below 7
    • Alkalines have a pH above 7
    • Neutral Substances have a pH of 7
INDICATORS CHANGE COLOR IN DIFFERENT PH
  • INDICATORS allow us to determine the pH of a substance without tasting or touching it.
  • Every indicator has a different range of pH that it is useful for and different color scales.
Bromophenol Blue effective range.
Phenol Red effective range.
Red cabbage juice has a big effective range.

Litmus Paper

This classic pH indicator is most successful at finding pH when pink and blue are both used to test a substance:

  • Base – (both blue) red turns blue and blue stays blue
  • Acid – (both red) red stays red and blue turns red
  • Neutral – (no change) red stays red and blue stays blue
ARE ACIDS OR BASES MORE DANGEROUS?
  • Weak acids like milk (pH 6) and weak bases like eggs (pH 8) aren’t dangerous.
  • But the farther the pH is from 7, the more dangerous a substance will be.
  • ACIDS are corrosive to metals so they should never be stored in metal containers.
  • Body structures like teeth and bones contain a lot of the metal Calcium and acidic substances can weaken them.
Batteries often go bad when the battery acid inside leak out and destroy the terminals.
A diet full of acidic foods can erode teeth away.
  • BASES are corrosive to non-metals.
  • Body structures like skin and organs contain a lot of non-metals and strong alkaline substances can damage them.
While exposure to bases doesn’t burn, they can react vigorously with skin and fat causing extensive damage.

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WATER ACIDIFICATION