Chemical changes Flashcards
What does the pH scale range from
0-14
Where are Acids and Alkalis on the pH scale
0-6.9 is acids
7 is neutral
7.1- 14 is alkalines
What can be used to measure the pH of a solution
An indicator like universal indicator that shows colours like the rainbow
What ions do acids and alkalines form
Acids- H+ ions
Alkaline- OH- ions
What is an acid
A substance that forms aqeous solution with a pH less than 7. Acids form H+ ions in water
What is a base
A substance with a pH over 7
What is an alkali
A substance that forms aqeous solution with a pH more than 7. Acids form OH- ions in water
What is the reaction between acids and bases called
Neutralisation
Give the generic formula of neutralisation reaction
Acid + Base –> Salt + Water
What is a strong acid and give an example
An acid that fully ionises an aqeous solution and all acid particles dissociate to release H+ ions
Example: HCl
What is a weak acid and give an example
An acid that only partially ionises in an aqeous solution and only a small proportion of acid particles dissociate to form H+ ions
Example: Ch3COOH- Ethanoic acid
Are strong or weak acids reversible
You can reverse weak acids dissociating by reacting it with other things.
What relates H+ ions and rate of reactions and how do strong and weak acids’ reactivities compare
If concentration of H+ ions is higher, the rate of reaction will be faster so strong acids will be more reactive than weak acids of the same concentration
How does concntration of hydrogen change as pH increases
It is a logarithmic scale, so the scale is 10^x when x is the pH change
What is the difference between a strong acid and a concentrated acid
Acid strength tells you what proportion of the acids is ionises
Acid concentrationis how much acid there is in a volume of water
What are metal oxides and metal hydroxides examples of
Bases