Strength versus concentration, how pH changes by one unit for every factor of 10 in hydrogen ion concentration, and titrations with their calculations.
What you will learn
- Tell a strong acid from a weak one, and strength from concentration
- Work out how many times the hydrogen ion concentration changes from a pH change
- Find a mean titre from concordant results
- Calculate a concentration from titration data
Strong, weak, concentrated, dilute (Higher)
A strong acid is completely ionised in water: every HCl molecule becomes H⁺ and Cl⁻.
Hydrochloric, nitric and sulfuric acids are strong.
A weak acid is only partially ionised: most ethanoic acid molecules stay whole. Ethanoic, citric and carbonic acids are weak.
Concentration is a different idea: how much acid is dissolved in each dm³. You can have a dilute strong acid or a concentrated weak one.
"Strong" is about how much of the acid ionises; "concentrated" is about how much acid there is. For the same concentration, a strong acid has a lower pH than a weak acid.
The rest of this lesson and its 15 practice questions are locked.
In this lesson
- Strong, weak, concentrated, dilute (Higher)
- pH and factors of 10 (Higher)
- Titrations (Chemistry only)
- Try it: Mr for mass concentration
15 practice questions, marked as you go; about 25 minutes in all.
Key terms
Strong acid, Weak acid, Concentration
In this unit: Chemical changes: reactivity, acids and electrolysis
The reactivity series and metal extraction, oxidation and reduction, acids, salts and pH, titrations, and electrolysis of melts and solutions.