acids and bases

• We measure the acidity or alkalinity of a solution using the PH scale.
• the pH scale ranges from 0-14
• pH 7 = neutral
• a pH of lower than 7 = acidic
• a pH of above 7 = Alkaline
• stomach acid typically has a pH of 2
• ways the pH of a solution can be measured:

  • chemical indicator
  • pH probe
• The pH of a solution can be measured using a type of chemical dye that changes colour, depending on the pH of the substance it's mixed with.

  This chemical dye is usually referred to as Indicator solution
• Universal indicator is made up of a several different indicator solutions. This means that it undergoes a smooth colour change over a wide range of pH values.

  • if it goes red its acidic
  • if it goes bluey purple its alkaline
•  reasons why using a probe may be more reliable than using an indicator:

  • more accurate result
  • Determining the colour of an indicator is subjective
• nitric acid:

  • HNO3
• calcium carbonate:

  •  CaCO3