Acids And Bases
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Acids have a low pH below 7 and turn litmus paper red, while bases have a high pH above 7 and turn litmus paper blue. Common acids include hydrochloric acid, sulfuric acid, and nitric acid found in stomach acid and some cleaners. Bases like bleach and those in toothpaste are often used to clean around the home. Water is neutral with a pH of 7, while indicators like litmus paper and universal indicator can test if a substance is an acid or base by changing color.
Acids And Bases
- 2. What are Acids? Acids are common Some are dangerous and can burn your skin Some are safe to eat and drink Stomach acid helps digest food explosion
- 3. Acids Definition All have low pH (0-6) Turn Litmus paper RED Taste Sour, Corrosive, Examples Hydrochloric HCl Sulfuric H 2 SO 4 Nitric HNO 3
- 4. What are Bases (Alkalis)? In our home we often use bases to clean things. Eg Bleach and toothpaste
- 5. Bases Definition Have a high pH (8-14) Turn litmus BLUE Examples Ammonia NH 3 Sodium Hydroxide NaOH Bleach Soap
- 6. Neutral Water is considered Neutral It is neither an acid or base It has a pH of 7
- 7. Measuring acid strength? To decide if something is an acid or a base we can use an indicator. Litmus and Universal Indicator are examples of indicators. They change color depending on if they are in an acid or a base.
- 8. Working with Indicators Red litmus turns BLUE in the presence of Bases (alkali) Blue litmus turns RED in the presence of acid Acids and bases react together in a NEUTRALISATION reaction
- 9. Acid Reactions Acid + Base Salt + Water Acid + Metal Salt + Hydrogen Acid + Carbonate Salt + Water + Carbon Dioxide Hydrochloric acids form CHLORIDE salts Nitric acid forms NITRATE salts Sulfuric acid forms SULFATE salts
- 10. Acid Rain Consider Causes natural human Effects buildings flora fauna health Chemical equations Prevention/Solution
Editor's Notes
- #2: Hcl and aluminium bomb Add bung rather than screw top?
- #3: Brainstorm understanding of acids (examples, what they do, how to test) fizz dissolve dangerous, dissolve metal, burn skin Name some in kitchen Vinegar, wine gone off, citric acid, batteries What taste sour H/O what do you know abt acid and base cut n paste Read aloud H/O acid burns Zn + HCl in test tube with balloon over the top, floats can be lit (pop test) Hindenberg
- #4: Demo 3 beakers add h20 pour into phenolpthaelin then base Mineral acids tend to be strong, donate lots H+ organic acids (carboxylic acids) are weak dont fully dissociate Learn these names and formula you will be tested EXPT Fair test planning for carbonate missile
- #5: Lesson 3 Kids write from board Acid and base are opposite one neutralises the other Toothpaste neutralises acids formed by plaque bacteria, bee sting (formic acid baking soda neutralise) Bases which are soluble in water are called alkalis (feel soapy as they turn oils on hands into soap) EXPT make soap see H/O
- #6: Ammonia in household cleaners NH# forms NH4+ and oh- (hydroxide ion) in water NaOH in oven cleaner, drain cleaner (dissolves grease)
- #8: Lesson 4 How do we test? Demo invisible writing use phenol pthaelin spray with alkali create a colour PH scale Indicators are extracted from plants (lichen) Ph is a measure of the conc of H+ in solution Chemicals which change colour in the presence of acids or bases EXPT universal indicator create rainbow in teams of 3 (H/O) colour ph scale naoh strong alkali, nh3 may need to dilute with water Homework bring in flower to make indicator
- #9: Lesson 5/6 Demo frothing rainbow (KISS)?????????????????? Draw on board word equation Reactants -- Products, Acid + base --- salt + water eg HCl + NaOH - NaCl + H2O ALWAYS OBSERVE WHEN MIXING CHEMICALS SMELL< FIZZ< HEAT< COLOUR ETC EXPT H/O indicators worksheet work in groups (make own indicator) EXPT find Ph of everyday substances H/O WRITE UP CORRECTLY, conclusion BLUE ALKALI, RED ACID< GREEN NEUTRAL
- #10: Lesson 7 Write then do the experment Hcl + NaOH -> NACl + H2O 2HNO3 + 2K -> 2KNO3 +H2 (note fizzing) H2SO4 + CaCO3 -> CaSO4 + H2O + CO2 (note fizzing) STALAGMITE formation limestone caves Taj mahal H/O Acids and bases rules revision H/O Mix and match overview
- #11: Lesson 8/9 (show acid rain ppt? research their own) RECAP was water neutral Why not Co2 in air dissolves to form carbonic acid h2co3 DEMO Marble chips added to H2SO4 OBSERVE fizz = gas Other Minerals dissolved sulfur dioxide, from power stations volcanoes forms h2so4 and nitrogen dioxide NO2 from car exhausts ACID RAIN Acid rain H/O and reading( poss read science world pg 256) CREATE POSTER causes of acid rain, chemical reaction involved, effect on buildings, plants , fish , humans include pictures, (might want flow diagram, mind map etc) PRESENT back to class