Topic 4 - Chemical Changes (No Pracs) Flashcards
(29 cards)
If a solution is acidic, is its pH low or high
Low
If a solution of alkali is its pH low or high
High
What’s the pH of a neutral solution
7
What are some ways to measure the pH of a solution
- indicators
- a pH probe
What ions do acids form in water
H+
In neutralisation what is a base
A substance with a pH greater than 7
What ions do alkalis form in water
OH-
What’s the general equation for neutralisation
Acid + base > salt + water
What are titrations used for
They are method of analysing concentrations of solutions
What are strong acids
Acids that ionise completely in water - all acid particles dissociate to release H+ ions
What are weak acids
Acids that do not fully ionise in solution
Is the ionisation of weak or strong acids a reversible reaction
Weak
Which are more reactive strong or weak acids
Strong
Why are strong acids more reactive
Reactions of acids involve the H+ ions reacting - strong acids have a higher concentration of H+ ions
For every decrease of 1 on the pH scale what happens to the concentration of H+ ions
It increases by a factor of 10
What happens to a the pH of a acid if you increase the concentration
The pH will decrease
What will reacting an acid with a metal oxide or a metal hydroxide form
A salt and water
What will a reaction of an acid and a metal carbonate form
Salt + water + carbon dioxide
What the mnemonic for the reactivity series
Peter said look calumn, my car zooms into hot countries
What do you get if you react an acid with a metal
Salt + hydrogen
How does reacting metals with acids show us their reactivity
The more reactive the metal the faster the reaction will go - measured by the rate of hydrogen bubbles given off, temperature change etc
What do you get if you react a metal with water
Metal hydroxide + hydrogen
Will all metal react with water
No - less reactive metals zinc, iron, and copper won’t
What time of reaction is the formation of metal ores
Oxidation
