Acids, Bases And Salts Flashcards
What is an acid?
A proton (H+) donor that release H+ in aqueous solutions.
Examples of 3 strong acids:
HCl
H2SO4
HNO3
What do strong acids do in solution?
They completely dissociate and release all their H+ ions
What is an example of a weak acid?
CH3COOH ethanoic acid
What do weak acids do in solution?
Partially dissociate as they don’t release all their H+ ions
What is a base?
A proton (H+) acceptor
What is an alkali?
A base dissolved in water that release OH- in aqueous solution
What are some examples of important bases?
Hydroxide
Oxides
Carbonates
Ammonia
Give some examples of strong alkalis and what do they do in solution?
NaOH KOH
They completely dissociate into separate ions
Why is ammonia a weak alkali?
In aqueous solution only some NH3 molecules react with water to produce a low concentration of OH-(aq)
Only partial dissociation
What is a salt and give some examples:
Produced whenever the H+ of an acid is replaced by a metal ion or NH4+
E.g chloride, nitrate, sulfate salts
What are the 4 neutralisation reaction equations to make a salt?
- Acid+ alkali -> salt + water
- Acid+ metal oxide -> salt + water
- Acid + carbonate -> salt+ carbon dioxide + water
- Acid + ammonia-> ammonium salt
What is the fifth way a salt can be made?
Acid + metal -> salt and hydrogen
What does an ionic equation show?
Shows the ions in a reaction that are CHANGED - even if it’s just there state
What happens in precipitation reactions of salt solutions?
A solid ionic compound forms when 2 ionic solutions are mixed
What is water of crystallisation?
The fixed number of water molecules within a hydrated crystal compound structure
(Represented by a dot followed by the fixed number)
What is a crystal?
A solid containing particles arranged in a regular way
What does a hydrated compound?
A crystalline compound that contains water molecules
What does an anhydrous compound mean?
A crystal compound contains no water molecules
What colour in copper(II) sulfate when hydrated and anhydrous?
Hydrated- blue crystals
Anhydrous- White crystals
How do you work out the water of crystallisation?
1. Find mass of water = mass of hydrated- mass of anhydrous 2. Find mole of water n=m/M 3. Work out mole of salt (anhydrous) n=m/M 4. Calculate the no of water present for 1 mole of salt with a ratio of the moles
When we heat the hydrated salt what must we make sure we do?
Re-heat until the mass no longer changes (to make sure all the water has evaporated)
Why might a water of crystallisation experiment not be accurate?
Some anhydrous salts decompose on strong heating
