Acids and Bases Science 10
Acids Taste sour (ex. lemons and vinegar) Are corrosive to your skin React and corrode metals (ex. Magnesium) Have an H in front of formula (ex. HCl, HBr) Good conductors of electricity
Bases Taste bitter Feel slippery Are also corrosive Found in many cleaning products (ex. Bleach, oven cleaners, ammonia) Have an OH on the right side of the formula (ex. Sodium hydroxide, ammonium hydroxide) Good conductors of electricity
Production of Ions Acids and Bases can conduct electricity because they release ions in solution Acids release hydrogen ions when dissolved in solution: H+ Bases release hydroxide ions when dissolved in solution: OH-
pH (parts of Hydrogen) The pH of a solution refers to the concentration of ions it has Testing the pH of a solution is a way of measuring its concentration of hydrogen ions A high concentration of H+ ions indicates a very acidic solution Square brackets are used to signify concentration: [H+] and [OH-] High [H+]=low pH, very acidic High [OH-]=high pH, very basic
pH Scale The strengths of acids and bases is measured on the pH scale pH below 7=acidic pH above 7=basic pH 7=neutral See Handout: Provincial Exam Data Booklet
Neutralization When an acidic solution is mixed with a basic solution, the solutions can NEUTRALIZE each other. In this case, the pH is 7 [H+] + [OH-] H2O
Using the pH scale 1 Stomach acid has a pH of _____ Tomatoes have a pH of ______. Each decrease of 1 on the pH scale indicates something is 10X more acidic Each increase of 1 on the pH scale indicates something is 10X more basic pH of 4 is ______X more acidic than a pH of 5 pH 3 is ______X more acidic than pH 6 Question: Are tomatoes or stomach acid more acidic, and by how much? 4 10 1000
pH Indicators The pH of acids and bases cannot be determined by sight but through chemicals called INDICATORS pH indicators change colour based on the solution they are placed in.
Examples of Indicators Litmus Paper Blue litmus paper turns red in acid (pH 0-6) Red litmus paper turns blue in base (pH 8-14) No color change=neutral or pH 7 Phenolphthalein Colorless in acids Pink in bases Color change occurs at pH 8.2-10.0
Using your Data Booklet fill in the following: Indigo Carmine Color change occurs at ____________ Changes from ________________ as pH increases Methyl Orange Changes from red to yellow as pH increases Color change occurs at ________________ Methyl Red Changes from ________________as pH increases Color change occurs at _________________ Bromythol Blue Changes from ___________________as pH increases
Using your Data Booklet fill in the following: Indigo Carmine Color change occurs at pH 11.2-13.0 Changes from blue to yellow as pH increases Methyl Orange Changes from red to yellow as pH increases Color change occurs at pH 3.2-4.4 Methyl Red Color change occurs at pH 4.8-6.0 Bromythol Blue Changes from yellow to blue as pH increases Color change occurs at pH 6-7.6
Summary Properties of Acids 1. Taste
Properties of Acids 1. Taste sour 2. Red litmus paper is
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is yellow 6. Acid solutions are ______electrical conductors
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is yellow 6. Acid solutions are good electrical conductors
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is yellow 6. Acid solutions are good electrical conductors 7. ________with active metals (Mg, Zn)
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is yellow 6. Acid solutions are good electrical conductors 7. React with active metals (Mg, Zn) 8. Neutralized by
Properties of Acids 1. Taste sour 2. Red litmus paper is red 3. Blue litmus paper is red 4. Phenolphthalein is colourless 5. Bromthymol blue is yellow 6. Acid solutions are good electrical conductors 7. React with active metals (Mg, Zn) 8. Neutralized by bases
Summary Properties of Bases 1. Taste
Properties of Bases 1. Taste bitter 2. Feel
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is blue 5. Phenolphthalein is
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is blue 5. Phenolphthalein is pink 6. Bromthymol blue is
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is blue 5. Phenolphthalein is pink 6. Bromthymol blue is blue 7. ______________ with active metals
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is blue 5. Phenolphthalein is pink 6. Bromthymol blue is blue 7. Do not react with active metals 8. Neutralized by
Properties of Bases 1. Taste bitter 2. Feel slippery (slimy) 3. Red litmus is blue 4. Blue litmus is blue 5. Phenolphthalein is pink 6. Bromthymol blue is blue 7. Do not react with active metals 8. Neutralized by acids
Homework Reading Check Page 225 #1-5 pH scale and pH indicators Worksheet (2-sided) Page 233 #1-8 http://www.youtube.com/watch?v=6Y4Y-__ME60 http://search.live.com/video/results.aspx?q=pH+and+indicators&docid=2768266527756&FORM=VIVR17#first=21&docid=2476336484055