62-65 - Acids and Alkalis and Salt Flashcards
What is universal indicator?
A dye which changes colour depending on a substance’s pH
What is a base?
A substance with a pH over 7
What is an alkali?
A base that dissolves in water
What makes a solution acidic?
Acids forming H+ ions
What makes a solution alkaline?
OH- ions from bases
What is the neutralisation reaction?
Acid + base -> salt + water
H+ + OH- -> H2O
What do acids and metals react to produce?
Acid + metal -> salt + hydrogen
How can hydrochloride acid be used to identify metals?
More reactive metals pop loudly
Why doesn’t copper react with dilute acids?
It is less reactive than hydrogen
What salt does hydrochloride acid produce?
Chloride
What salt does sulfuric acid produce?
Sulfate
How is the name of a salt determined?
Metal - acid
e.g. magnesium chloride
Are metal oxides/hydroxides acids or bases?
Bases
What do metal oxides or hdroxides give when reacting with acid?
Acid + metal oxide -> Salt + water
Why might ammonia be neutralised?
For fertiliser
What is often used to neutralise ammonia?
Nitric acid
What is the symbol equation for the neutralisation of ammonia?
NH3 + HNO3 -> NH4NO3
Which salts are usually soluble?
Chlorides, sulfates, nitrates
Which salts are usually insoluble?
Oxides, hydroxides
What two methods are there of making soluble salts?
With acid and metal/insoluble base
With an alkali
What is crystallisation?
Letting a solution containing salt slowly evaporate
What does it mean when salt forms at the bottom of a solution?
It has been neutralised
How do you separate salt from a solution?
Filter out metal
Evaporate water
Let it crystallise
How do you make an insoluble salt?
Precipitation reaction
