6.2 Strong Acids & Weak Acids Flashcards
Acids ionise. What does this mean?
They produce hydrogen ions
What is an acid?
A substance that forms aqueous solutions with a pH less than 7
What happens to strong acids in water?
All of the acid particles will dissociate to release hydrogen ions - the reactants will turn completely into products
What happens to weak acids in water?
Only a small proportion of the acid molecules dissociate to release hydrogen ions
Why do weak acid particles only partly dissociate in water to form hydrogen ions?
As the ionisation of a weak acid is reversible, which means theres an equilibrium between the undissociated and the dissociated forms of the acid
What does a reversible reaction do?
As well as the reactants being able to form products, the products can react to reform the reactants
As only a few particles dissociate in weak acids, we say that the equilibrium lies far to the left. What does this mean?
At equilibrium we will have far more molecules of undissociated acid than we will molecules of dissociated acid
What is the strength of an acid dependent on?
What proportion of the acid molecules ionise in water
What is the concentration of an acid dependent on?
How much acid there is in a certain volume of
Reactions of acids involve the reactions of the ________ ions with other substances
hydrogen
What is pH?
A measure of the concentration of hydrogen ions in a solution
What happens to the pH when the concentration of hydrogen ions gets higher?
It gets lower
What does each pH of 1 represent on the pH scale, as the numbers go down?
The concentration of hydrogen ions increasing by a factor of 10
Why would a strong acid be able to have a low pH at most concentrations?
As each particle dissociates fully and so overall we would have many hydrogen ions being released
Why would a weak acid have to be highly concentrated to have a low pH?
As so few of the acid particles would actually ionise and release their hydrogen ions
