pH Year 11

Explain how pH is determined

Use a pH scale to compare solutions

The quantitative measure of the acidity or basicity of aqueous or other liquid solutions.

Translates the values of the concentration of the hydrogen ion—which ordinarily ranges between about 1 and 10⁻¹⁴ gram-equivalents per litre—into numbers between 0 and 14.

When dissolved in water, an acid releases hydrogen ions (H+) and the solution becomes acidic

If a solution has a high concentration of H+ ions, then it is acidic, with a low pH number.

Many of our foods are acidic - oranges, apples, tomato sauce.

Acids taste sour and feel "squeaky" when you rub your fingers together.

When a base is mixed with water, it releases hydroxide ions (OH‐)

If a solution has a high concentration of OH‐ ions, then it is basic, and has a high pH number.

Many of our cleaning products are basic - windex, soap and bleach.

Bases taste bitter and feel slippery.

Strong acids and bases ionise almost completely in water, contributing many ions.

Weak acids and bases ionise incompletely, contributing a few ions.