Lesson · S.3.6
Acids and bases
The pH scale and what makes a solution acidic, basic, or neutral, with the everyday examples the TEAS uses to test it.
ObjectiveS.3.6Read2 minExam weightChemistry ≈ 18% of Science
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- Place a solution on the pH scale as acidic, basic, or neutral.
- Explain why a whole-number change in pH means a tenfold change in hydrogen ion concentration.
- Describe what happens to hydrogen and hydroxide ions during neutralisation.
What the lesson concludes
- The pH scale runs 0 to 14; below 7 is acidic, above 7 is basic, and 7 is neutral.
- Each whole step on the scale is a tenfold change in hydrogen ion concentration.
- Acids release hydrogen ions; bases release hydroxide ions or accept hydrogen ions.
- Neutralisation combines an acid and a base to form water and a salt.
- The body uses buffers to hold blood pH close to 7.4 despite small chemical shifts.