acids, bases and ph scale
DESCRIPTION
Acids, Bases and pH scale. ACIDS. Compound that releases Hydrogen ions (H+). Examples of Common Acids. Hydrochloric acid – HCl Hydrosulfuric acid – H 2 SO 4 Nitric acid – H 2 NO 3 What do these formulas have in common?. Acetic Acid - Vinegar HC 2 H 3 O 2. Lactic Acid. - PowerPoint PPT PresentationTRANSCRIPT
Acids, Bases and pH scale
ACIDS
• Compound that releases Hydrogen ions (H+)
Examples of Common Acids
• Hydrochloric acid – HCl• Hydrosulfuric acid – H2SO4
• Nitric acid – H2NO3
What do these formulas have in common?
Acetic Acid - Vinegar
HC2H3O2
Lactic Acid
•Found in foods like yogurt and cottage cheese and sourdough bread
•Causes muscle soreness
Citric Acid
•Found abundantly in citrus fruits (lemons, oranges, grapefruit)•Used to add a sour taste to foods •Flavoring in soft drinks
Formic Acid
• In the venom of ants and bees HCO2H
Amino Acids• “Building blocks” of protein molecules
Bases
•Bases are compounds that release Hydroxide ions (OH -) in water. • Also called alkalines.
Examples of Common Bases
Sodium hydroxide – NaOHCalcium hydroxide – CaOHMagnesium hydroxide – Mg(OH)2
Most soaps and detergents are basic
All compounds are eitherAcids, Bases, or Neither
HFH2SO4
CaOHMg(OH)2
C6H12O6
HClNaClAl(OH)2
Chemical Formula Acid Base Neither
pH
The measurement of the amount of H+ (hydrogen ions) in solution
pH Scale - Range is 0 - 14
0 1 2 3 4 5 6 7__ 8 9 10 11 12 13 14
1.311.477.0010.16.9993.8913.00.0
pH Acid Base Neutral
Determining a compound’s property from its pH value
Most living things must live in an environment of pH 6.5 – 7.5
HOWEVER, there are some exceptions:
•Acidophiles – bacteria that live in highly acidic environments. They have evolved a variety of specialized mechanisms to maintain their intracellular pH at a constant level (usually 7.2). Example: L. acidophilus breaks down food in the intestine
• Specialized cells in stomach lining make HCl “stomach acid” of pH 1
Parietal Cells
• Azalea plants thrive in acidic soil of pH 4.5
Soil pH
• Alkaline soil makes hydrangeas pink
• Acidic soil makes hydrangeas blue
Buffers
• Help prevent any large changes in pH
• Buffers are molecules that can bind to an H+ ion when the H+ concentration increases - “locks” it up so the solution doesn’t get more acidic
• Releases an H+ ion when the H+ concentration decreases
Blood pH and Buffers
• Normal pH of blood between 7.35 - 7.45
• Less than 6.8 or greater than 7.8 is deadly
• Buffers in blood help prevent any large change in blood pH