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?
Think about it
Acidic drinks lower the pH in your mouth. How does something basic protect your enamel?
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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