Understanding acids and bases.ppt 2012

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Transcript of Understanding acids and bases.ppt 2012

  • 1.Acids andBases

2. Understanding Acids and BasesDistilled Water 7 - ish Saliva 6 -7.4Tap Water 7.5-8 Battery Acid .5-1Baking Soda 8.5 - 9 Stomach Acid .5-1Lemon Juice 2.5-3 Milk 6.5Normal Rain 5.6-6.5 Ammonia11-12Vinegar 2.5-3 Orange Juice 3.5Drain Cleaner 12 - 14 Cola 2.5-4(NaOH) 3. Putting it all Together 4. Characteristics of Acids Taste sour pH less than 7 Corrode Metal Conduct electricity very well (bases will also conduct electricity but not as well as acids) 5. Characteristics of Bases pH greater than 7 Taste bitter GoodCleaners Feel slippery 6. Understanding the pHScaleAcidicBasic0714NeutralThe pH scale is a logrithmic scale.A difference of one pH unit represents a tenfold changeA difference of 2 pH units, for example from 6 to 4, would mean thatthe acidity one hundred times greater. 7. Check Your UnderstandingHow many times more acidic is atomato than coffee?10How many times more acidic istomato than saliva?100How many times more acidic is lemonjuice than coffee?1,000 8. What kinds ofIndicators arethere? 9. What makes a solution an acid?What makes a solution a base? 10. Is There a PatternHere?A = HCl E = HNO3B = H2SO4 F = H3BO3C = NaOHG = NH4OHD = KOH H = CaOH 11. Questions? 12. Acid Base Review 13. What is the pH scale? A numerical scale 0-14 that is used to measure how acidic or alkaline a substance is. 14. What is phenopthalein? A base indicator. It turns bright pink when put into a base.+ 15. What is bromythymol blue? An universal indicator.It turns yellow when placed in an acid. Bright blue in base. Mostly used to detect carbonic acid. 16. What is Universal Indicator and howcan you use it to test an unknown solution? An acid/base indicator.It turns different colors depending upon the strength of the acid and base. You use a color chart to find the number that corresponds to the pH scale. 17. How does the pH number of a strongacid compare to the pH of a weak acid? A strong acid will have a pH of 0-1. A strong base will have a pH of 13-14 18. What is the difference between an acid and a base? An acid has a H ion. A base has a hydroxide ion. 19. What sort of foods are acids? lemons, oranges, anything with citric acid.Also milk is slightly acidic. 20. What sort of liquids are cleaners? Bases 21. What do acids taste like? sour 22. What liquid is neutral? pure water 23. How can you compare strengths of acids using the pH scale? For every number difference on the pH scale, itis that many power of ten times more acidic. Hard to explain.. For instance.. If yourecomparing something with a pH of 2 tosomething with a pH of 6. the pH of 2 is tenthousand times more acidic than the pH of six. 6-2=4.. that means its 10 to the fourthpower stronger. Ten to the fourth is 10,000 24. What is the pH range of normal rain? 5.6-6.5 25. What is the pH range of acid rain? Below 5.6 26. What acid does carbon dioxide form inwater? Carbonic Acid 27. What is meant by the term"neutralization"? Adding base to an acid until it becomes pH close to 7