Acids Flashcards
What state are Metal Carbonates normally?
Solid
What are three soluble metal carbonates?
-Na2CO3
-K2CO3
-(NH4)2CO3
(all aq)
What is an acid?
Acids release H+ ions in aqueous solution so they are defined as a proton (H+) donor
What do alkalis release in an aqueous solution?
OH-
What element do all acids contain?
Hydrogen
What are the important acids?
-HCl
-HNO3 (nitric)
-H2SO4 (sulphuric)
-CH3COOH (ethanoic acid)
What are 2 common alkalis?
NH3
Metal hydroxides and carbonates
What are strong acids?
-Proton donors that completely dissociate in aqueous solution
(HCl)
What are weak acids?
Proton donors that partially dissociate in aqueous solution (giving and equilibrium mixture)
What happens when you put weak acids in solution?
-Only a small percentage of the acid molecules dissociate
What are examples of strong acids?
-HCl
-H2SO4
-HNO3
What is a base?
-Bases neutralise acids to form salts
-Defined as a proton acceptor
What are examples of bases?
-Metal Hydroxides- Mg(OH)2
-Metal Carbonates- Na2CO3
-NH3
Why is CuO a base?
It is insoluble in water
What is an alkali?
A base that dissolve in water releasing hydroxide ions
Why is ammonia is classed as an alkali?
When it is added or water, ammonium ion and hydroxide ions are formed
What are the most common alkalis?
-NaOH
-KOH
-NH3
What are all group 1 metal hydroxides?
Soluble in water and can form alkalis
What is neutralisation?
When an acid reacts with a base to form a salt and water
What happens during a neutralisation reaction?
The H+ ions from the acid are replaced by metal ammonium ions
What does an acid + alkali and an acid + metal oxide make?
Salt + water
What does an acid + (metal) carbonate make?
Salt + water + carbon dioxide
What does an acid + ammonia make?
Ammonium salt
What does a metal + acid make?
salt + hydrogen
Why will there be effervescence when an acid + (metal) carbonate react?
CO2 has evolved and the solid CO2 will dissolve
What are the observations for the acid base reactions:
-acid + solid carbonate
-acid + solid metal oxide
-acid + reactive metal
-Fizzing
-Solid disappears
-Colourless solution forms
what are the observations for the acid base reactions:
-acid + aqueous carbonate
-acid+ aqueous metal hydroxide
-No fizzing
-No solid disappears (N/A)
-Colourless Solution forms
What can titrations be used to do?
-Find conc of a solution
-Identify unknown compounds
-Determine percentage purity
What are standard solutions?
Solutions is known concentrations
What can we do in a titration?
accurately measure the volume of one solution that reacts exactly with another solution
How do you prepare a 250cm3 standard solution? (starting from a solid)
-weigh by diff the mass of is acid into a beaker using a mass balance
-add enough distilled water to beaker to dissolve the solid
-transfer solution into a volumetric flask using a funnel
-rinse and transfer any residue down beaker and funnel into the volumetric flask
-Add distilled water up to the graduation line in the flask
-As you approach the graduation line add the water drop-wise using a pipette and ensure the bottom on the meniscus lines up with exactly with the mark
-Stopper the flask and mix by inversion
What should the results of a tritiation be?
-Accurate
-Repeatable
When is the a titration technique used good/consistent?
If the results are concordant or close
What happens if salt solutions are left to evaporate at room temp?
-The hydrated salts are formed
What does a hydrated salt have?
-The metal ion, the counter ion and water of crystallisation
How is a hydrated salt quantified?
by heating until the mass remains constant when solid is cooled
What is an example of a hydrated salt?
hydrated copper (ii) sulfate
What is the metal ion in hydrated copper (ii) sulfate?
Cu2+
what is the counter ion in hydrated copper (ii) sulfate?
SO42-
What is the formulae for hydrated copper (ii) sulfate?
CuSO4•5H2O
What is an anhydrous salt?
-CuSO4
What is the water of crystallisation?
5H2O
What is the hydrated salt?
CuSO4•5H2O (blue)
