Acidic environment: Dot point 1

Acidic environment: Dot point 1

1. 1.1: Classify common substances as acidic, basic or neutral

   • Acid
     • Properties
       • In solution, it produces hydrogen ions, H+, or more strictly H3O+, called hydronium ions
       • Have a sour taste
       • They sting or burn the skin
       • In solution, they conduct electricity
     • Common Substances
       • Common Acids
   • Basic
     • Properties
       • Contains the oxide (O2-) or hydroxide ion (OH-) or which in solution produces the hydroxide ion
       • Have a soapy feel
       • Have a bitter taste
       • In solution, alkalis are good conductors
     • Common Substances
       • Common Bases

2. 1.2: Identify that indicators such as litmus, phenolphthalein, methyl orange and bromothymol blue can be used to determine the acidic or basic nature of a material over a range , and that the range is identified by change in indicator change

   • Experiment
     • Aim: To prepare acidic and alkaline solutions of different concentrations and use these to investigate the colour change in a range of indicators.
     • Equipment
       • Equipment for 1.2
     • Safety inspection: Wear safety goggles. Sodium hydroxide is caustic (able to burn or corrode organic tissue) and hydrochloric acid is corrosive. Avoid contact with skin. If contact occurs, wash with plenty of water and soap.
     • Results
       • Results for 1.2
     • Procedure
       • Procedure for 1.2

3. 1.3: Identify and describe some everyday uses of indicators including the testing of soil acidity/basicity

   • Soil Testing
     • Some plants grow best in acidic soils; others need slightly alkaline (basic) conditions. Farmers and keen gardeners use simple test kits containing an indicator and colour chart, to test the soil. They can then adjust the soil pH to get the best results
   • Water Testing
     • Swimming pools need regular testing for acidity to better maintain their water quality and hygiene. Aquariums must be maintained at very specific pH levels for the health of their inhabitants.
   • Effluent (Liquid waste or sewage) Testing
     • We can use indicators to assess the acidity levels of certain types of pollution from industries. Industry technicians and government authorities use indicators to monitor the pH of waste water and natural waterways.

4. 1.4: Perform a first hand investigation to prepare and test a natural indicator

   • Aim: To prepare an indicator solution from red cabbage and test the resulting indicator on a range of substances
   • Safety Inspection: Wear safety glasses. Sodium hydroxide is caustic and hydrochloric acid is corrosive. Avoid contact with skin. If contact occurs wash with plenty of water.
   • Equipment
     • Equipment for 1.4
   • Procedure
     • Equipment for 1.4
   • Results
     • Results for 1.4