Definitions of acids and bases Flashcards
What is an acid?
A hydrogen ion donor
What is a base?
A hydrogen ion acceptor
What is an alkali?
A base that can dissolve in water
What color does universal indicator turn with bases?
Purple or blue
What color does universal indicator turn with acids?
Red
How is pH related to how vigorously an acid reacts with a metal?
The lower the pH, the more vigorous the reaction is
What does pH actually measure?
The concentration of hydrogen ions
Why does an acid with a low pH react more vigorously?
An acid with a low pH has a higher concentration of hydrogen ions
What happens for every increase by 1 on the pH scale?
The concentration of hydrogen ions decreases by a factor of 10
Why does sulphuric acid have a lower pH that hydrochloric acid at the same concentration (e.g. 0.1 mol/dm3) ?
One molecule of sulphuric acid produces 2 hydrogen ions, while a molecule of hydrochloric acid produces just 1. Sulphuric acid has double the number of hydrogen ions at the same concentration.
What is a strong acid?
An acid that fully dissociates into hydrogen ions when dissolved in water
What is a weak acid?
An acid that only partially dissociates into hydrogen ions when dissolved in water. There are more molecules that don’t split up than molecules that do
When is the only time that a weak acid can have a lower pH (more hydrogen ions) than a strong acid ?
When the weak acid is at a much higher concentration than the strong acid.
