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ACIDS AND BASES

ACIDS AND BASES. CHARACTERISTICS OF ACIDS. PRODUCE EXCESS HYDROGEN IONS HAVE A POSITIVE ELECTRICAL CHARGE ARE PROTON DONORS ARE ELECTRON ACCEPTORS TASTE SOUR TURN LITMUS RED HAVE PH OF 1.0-6.9. PRODUCE EXCESS HYDROGEN IONS.

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ACIDS AND BASES

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  1. ACIDS AND BASES

  2. CHARACTERISTICS OF ACIDS • PRODUCE EXCESS HYDROGEN IONS • HAVE A POSITIVE ELECTRICAL CHARGE • ARE PROTON DONORS • ARE ELECTRON ACCEPTORS • TASTE SOUR • TURN LITMUS RED • HAVE PH OF 1.0-6.9

  3. PRODUCE EXCESS HYDROGEN IONS • WHEN ACIDS DISSOLVE IN WATER, THEIR MOLECULES BREAK APART AND RELEASE HYDROGEN IONS IN TO THE SOLUTION • H 2O +HCL  H+ + OH + HCL  H+ + CLOH2

  4. PROTON DONORS/ELECTRON ACCEPTORS • IN CHEMICAL REACTIONS, ACIDS DONATE HYDROGEN IONS (H+) • HYDROGEN ONLY HAS ONE ELECTRON TO GIVE UP THEREFORE HYDROGEN ION IS A SINGLE PROTON • THUS ACIDS ARE COMPOUNDS THAT EASILY GIVE UP THE PROTON FROM A HYDROGEN ATOM, MAKING THEM PROTON DONORS

  5. SOUR TASTE • NOT ALL ACIDS ARE SAFE TO TASTE • ACID FOODS IN THE KITCHEN ARE SAFE TO TASTE • EXAMPLES INCLUDE LEMONS, GRAPEFRUIT, VINEGAR, YOGURT

  6. PH 1.0-6.9 , TURN LITMUS RED • THE LOWER THE PH THE MORE CAUSTIC • WITH RED CABBAGE OR LITMUS, ACIDS TURN RED OR PINK • COMMON FOODS PH LEVELS • LEMON JUICE 2.2-2.4 • CHEESE 4.0-4.5 • WHITE BLEACHED FLOUR 5.7-5.9

  7. BASES (CHEMICAL OPPOSITES OF ACIDS) • PRODUCE EXCESS HYDROXIDE IONS • HAVE A NEGATIVE ELECTRICAL CHARGE • ARE PROTON ACCEPTORS • ARE ELECTRON DONORS • TASTE BITTER • TURN LITMUS BLUE • HAVE A PH OF 7.1-14.0

  8. PRODUCE EXCESS HYDROXIDE IONS • IN WATER WILL RELEASE HYDROXIDE IONS • NH3 + H20  NH4 + OH-

  9. PROTON ACCEPTOR/ ELECTRON DONOR • SINCE BASES RELEASE HYDROXIDE IONS (OH-) IN WATER, THEY ARE NEGATIVELY CHARGED BEING NEGATIVELY CHARGED, THEY WILL ACCEPT PROTONS AND GIVE UP ELECTRONS ( IF AN ACID AND A BASE COMBINE TO FORM A COMPOUND WITH IONIC BONDS, IT IS A SALT)

  10. TASTE BITTER • NOT ALL BASES ARE SAFE TO TASTE • COMMON HOUSEHOLD BASES • BAKING SODA • MILK OF MAGNESIA • DRAIN CLEANER • SOAP (SLIPPERY FEEL IS PROPERTY OF BASE) • WINDOW CLEANER

  11. PH OF 7.1-14.0, BLUE LITMUS • THE HIGHER THE PH THE MORE CAUSTIC • WITH RED CABBAGE OR LITMUS PAPER BASES TURN BLUE • COMMON FOODS PH LEVEL • EGGS 6.4-9.7 • CRACKERS 7.0-8.5 • DEVILS FOOD CAKE 7.5-9.0

  12. ACIDS AND BASES IN THE BODY • BLOOD – PH 7.4, SLIGHTLY BASIC • LOWER THAN 7.2 (ACIDOSIS) OR HIGHER THAN 7.6 (ALKALOSIS) CAN CAUSE • DULLING OF THE BREATHING REFLEX • FATIGUE • CONFUSION • COMA • DEATH

  13. BUFFERS IN BLOOD • BUFFER SYSTEM KEEPS PH WHERE IT SHOULD BE • CELL WASTE PRODUCT IS CO2 • BECOMES CARBONIC ACID (H2CO3) IN BLOOD WHICH KEEPS BLOOD FROM BEING TOO BASIC • BLOOD MOLECULES HAVE PHOSPHATE OR BICARBONATE IONS THAT NEUTRALIZE EXCESS CARBONIC ACID KEEPING BLOOD FROM BEING TOO ACIDIC

  14. DIGESTION • VARIOUS LEVELS OF PH NEEDED IN DIGESTION PROCESS • SALIVA- PH OF 6.5 • GASTRIC JUICES – PH OF 1.5-1.7 • PANCREATIC JUICE- 8.0 • BILE FROM GALL BLADDER – 8.4 • SMALL INTESTINE – 7.0

  15. FOOD PRESERVATION • FOOD BORNE ILLNESS CAUSED BY MICROORGANISMS FEEDING ON FOOD • MICROORGANISMS GROW BEST A SPECIFIC PH FOR THAT ORGANISM • MOST NEED 5.0-7.0 • CHANGE THE PH HIGHER OR LOWER AND YOU WILL CREATE AN ATMOSPHERE THAT IS NOT IDEAL FOR THAT MICROORGANISM

  16. EXAMPLES • CLOSTRIDIUM BOTULINUM WILL NOT PRODUCE DEADLY TOXIN IF PH IS 4.6 OR LOWER • LOW ACID FOODS CAN BE PICKLED TO INCREASE THEIR ACIDITY TO PREVENT SPOILAGE • SALTS KILL BACTERIA THROUGH DEHYDRATION (SALT IS ABUNDANT, INEXPENSIVE AND WORKS WITHOUT REFRIGERATION OR SPECIAL CANNING MAKING IT A METHOD USED FOR CENTURIES)

  17. BAKING • CHEMICAL LEAVENING AGENTS—INGREDIENTS ADDED TO BAKED GOODS TO LIGHTEN OR AERATE THEM • BAKING SODA • BAKING POWDER (BAKING SODA, DRY ACIDS, AND FILLERS) • DOUBLE ACTING BAKING POWDER (HAS 2 ACIDS, ONE THAT WORKS WHEN WET AND ONE THAT WORKS WITH HEAT) • CREAM OF TARTAR (ONE OF THE MOISTURE ACTIVATED ACIDS IN BAKING POWDER)

  18. MIXING ACIDS AND BASES IN BAKING • BAKING SODA IS A BASE • COMBINE BAKING SODA WITH AN ACID AND CARBON DIOXIDE IS RELEASED • COMMON ACIDS ARE VINEGAR, LEMON JUICE, BUTTERMILK, CREAM OF TARTAR • NAHCO2 + CH3COOH  NA(CH3COO) + H2O + CO2 • (BAKING SODA + VINEGAR)

  19. RESULTS IN BAKING • IF BATTER OR DOUGH IS OVERMIXED WITH PRODUCT THAT HAS A LIQUID ACTIVATED LEAVENING AGENT THEN THE C02 THAT IS A BY-PRODUCT CAN BE WORKED OUT OF THE MIXTURE, PREVENTING PROPER RISING • VERY IMPORTANT TO FINISH MIXING QUICKLY AND BAKE AS SOON AS POSSIBLE WHEN USING CHEMICAL LEAVENING AGENTS

  20. INDUSTRY IMPORTANCE • ACID DEVELOPS AS FRUIT MATURES, ACIDS IMPROVE JUICE QUALITY, COLOR, AND INCREASE SUGAR CONTENT, WINE INDUSTRY CHECKS PH BEFORE HARVESTING GRAPES • CITRUS FRUITS BALANCE BETWEERN SWEETNESS OF SUGARS IN FRUIT AND THE SOUR ACID TASTE, ONCE PICKED PROCESSES STOP, CHECK PH TO DETERMINE WHEN TO HARVEST

  21. resources • Mehas, Kay and Sharon Rodgers. Food Science: the Biochemistry of Food and Nutrition. Glencoe, New York, NY, 2006. • Ward, Janet. Principles of Food Science.Goodheart-Wilcox, Tinley Park, Illinois, 2007.

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