Acids and Bases

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Acids and Bases

  1. 1. Warm-up <ul><li>Name the following: </li></ul><ul><li>LiBr </li></ul><ul><ul><li>lithium bromide </li></ul></ul><ul><li>Be(NO 3 ) 2 </li></ul><ul><ul><li>beryllium nitrate </li></ul></ul><ul><li>NO </li></ul><ul><ul><li>nitrogen monoxide </li></ul></ul>
  2. 2. Warm-up <ul><li>List the four factors that affect reaction rates? </li></ul><ul><li>Temperature </li></ul><ul><ul><li>High temperature – fast reaction </li></ul></ul><ul><ul><li>Low temperature – slow reaction </li></ul></ul><ul><li>Surface area </li></ul><ul><ul><li>Large surface area – fast reaction </li></ul></ul><ul><ul><li>Small surface area – slow reaction </li></ul></ul><ul><li>Stirring </li></ul><ul><ul><li>Fast stirring – fast reaction </li></ul></ul><ul><ul><li>Slow stirring – slow reaction </li></ul></ul><ul><li>Concentration </li></ul><ul><ul><li>High concentration – fast reaction </li></ul></ul><ul><ul><li>Low concentration – slow reaction </li></ul></ul>
  3. 3. 5-9: Acids & Bases <ul><li>Identify characteristics of acids & bases. </li></ul><ul><li>Compare acids & bases. </li></ul>
  4. 5. Acids and Bases <ul><li>Produce H+ ions in water </li></ul><ul><li>Have a sour taste </li></ul><ul><li>Break down metals </li></ul><ul><li>Poisonous and corrosive to skin </li></ul><ul><li>Formula starts with H </li></ul><ul><li>pH less than 7 </li></ul><ul><li>Produce OH- ions in water </li></ul><ul><li>Have a bitter taste and a slippery feel </li></ul><ul><li>Break down fats and oils </li></ul><ul><li>Poisonous and corrosive to skin </li></ul><ul><li>Formula ends with OH </li></ul><ul><li>pH greater than 7 </li></ul>
  5. 6. Acids and Bases <ul><li>ACIDS </li></ul><ul><li>Examples: vinegar, lemon juice, aspirin, stomach acid, battery acid, cola, </li></ul><ul><li>BASES </li></ul><ul><li>Examples: soap, shampoo, ammonia, drain cleaner, antacids </li></ul><ul><li>milk </li></ul>
  6. 7. Acids <ul><li>An acid is a substance that ionizes in water to produce hydrogen ions (H + ) </li></ul><ul><li>Strength </li></ul><ul><ul><li>Strong acids completely ionize in water. </li></ul></ul><ul><ul><li>Weak acids ionize only slightly. </li></ul></ul>
  7. 8. Base <ul><li>A base is a substance that ionizes in water to produce hydroxide ions (OH - ) </li></ul><ul><li>Strength </li></ul><ul><ul><li>Strong bases ionize completely. </li></ul></ul><ul><ul><li>Weak bases do not. </li></ul></ul>
  8. 9. Basic Acidic Neutral H+ H+ H+ OH- OH- OH- Solution Solution Solution Which solution is Acidic? Basic? Neutral???
  9. 10. pH Scale <ul><li>Numeric scale that tells the acidity or basicity (alkalinity) of substances. </li></ul><ul><li>0 7 14 </li></ul><ul><li>Strong Acid Weak Acid Neutral Weak Base Strong Base </li></ul>
  10. 11. Neutralization Reactions <ul><li>When an acid is added to a base, they neutralize each other. (ie, the end products are neutral) </li></ul><ul><li>Acid + Base  Salt + Water </li></ul><ul><li>HCl + NaOH  NaCl + H 2 O </li></ul><ul><li>H 2 SO 4 + Al(OH) 3  Al 2 (SO 4 ) 3 + H 2 O </li></ul><ul><li>Salt – the neutral product of an acid/base rxn </li></ul>
  11. 12. pH Indicators <ul><li>Chemical substance that changes color in an acid or a base. </li></ul><ul><li>pH paper; </li></ul><ul><ul><li>paper strips dipped in universal indicator; </li></ul></ul><ul><ul><ul><li>red in acid, </li></ul></ul></ul><ul><ul><ul><li>green in neutral substance, </li></ul></ul></ul><ul><ul><ul><li>purple in base </li></ul></ul></ul><ul><ul><ul><li>match the color to a number on the vial to determine pH </li></ul></ul></ul>
  12. 13. Litmus Test <ul><li>Litmus paper; paper strips dipped in red and blue litmus; </li></ul><ul><li>Tells definitively whether the substance is an acid or base. “Litmus Test” </li></ul><ul><li>Dip one red and one blue strip & check results: </li></ul><ul><ul><ul><li>Red -> Red = Acid </li></ul></ul></ul><ul><ul><ul><li>Blue -> Red = Acid </li></ul></ul></ul><ul><ul><ul><li>Red -> Blue = Base </li></ul></ul></ul><ul><ul><ul><li>Blue -> Blue= Base </li></ul></ul></ul><ul><ul><ul><li>Red -> Red = Neutral </li></ul></ul></ul><ul><ul><ul><li>Blue -> Blue= Neutral </li></ul></ul></ul>
  13. 14. Other pH indicators <ul><li>Phenolthalein </li></ul><ul><ul><li>Pink – pH is greater than 9 </li></ul></ul><ul><ul><li>Clear – pH is lower than 9 </li></ul></ul><ul><ul><li>Only indicates strong bases </li></ul></ul><ul><ul><ul><li>Strong Base – Pink </li></ul></ul></ul><ul><ul><ul><li>Weak Base – Clear </li></ul></ul></ul><ul><ul><ul><li>Neutral – Clear </li></ul></ul></ul><ul><ul><ul><li>Weak Acid – Clear </li></ul></ul></ul><ul><ul><ul><li>Strong Acid – Clear </li></ul></ul></ul><ul><li>Bromothymol Blue </li></ul><ul><ul><li>Base – Blue </li></ul></ul><ul><ul><li>Neutral – Green </li></ul></ul><ul><ul><li>Acid – Yellow </li></ul></ul>

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