Grade 10 · Acids, Bases and Solutions · Acids and Bases
Acids, Bases and pH
The pH scale, indicators and neutralisation.
Learning objectives
- Describe the pH scale.
- Identify acids and bases using indicators.
- Write a general neutralisation equation.
NGSS alignment
MS-ESS3-3
Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
HS-PS1-2
Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
MS-PS1-2
Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
MYP criteria
- Criterion A — Knowing and Understanding
- Criterion D — Reflecting on the Impacts of Science
ENGAGE
Why does toothpaste help after an acidic drink?
EXPLAIN
The pH scale
- pH below 7: acidic; pH 7: neutral; above 7: basic (alkaline).
- Universal indicator shows pH by colour; litmus gives a quick acid/base test.
- Neutralisation: acid + base gives salt + water.
Remember
Each whole pH step is a tenfold change in acidity, so pH 3 is ten times more acidic than pH 4.
Interactive simulation · PhET
pH Scale: Basics
Test each liquid with the pH probe, then dilute an acid with water and watch the pH move.
While you explore
- Which liquids are acidic, neutral and basic?
- What happens to pH when you add water to an acid?
- How does the number of H+ ions relate to pH?
Practice questions
0/2 correct
Level 1
A solution has pH 2. It is...
Level 2
Which equation represents neutralisation?
Reflect & track
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