acids and bases and salt preperations Flashcards
what is an acid
An acid contains hydrogen, and releases hydrogen ions in reactions
what is a salt
Salt = a compound when a metal replaces the hydrogen in an acid
what is HNO3
HNO3 = nitric acid
what is ammonia chemical formula
NH3 = ammonia
chemical formula for phosphoric acid
H3PO4 = phosphoric acid
chemical formula for ethanoic acid
CH3COOH = ethanoic acid
what happens when a hydrogen is replaced by an ammonium molecule
When the hydrogen is replaced by an ammonium molecule instead of a metal, it becomes an ammonium salt
chemical formula for ammonium
Ammonium = NH4+
list all general equations (6)
acid+base –> salt +water
acid +metal –> salt + H2
acid + metal oxide –> salt + H2O
acid + metal hydroxide –> salt + H2O
acid + metal carbonate –> salt + CO2 + H2O
acid + ammonia–> ammonium salt + water
what is effervescence
When gas a produced in a chemical reaction, it is called effervescence
How can you confirm that the gas produced in this reaction is hydrogen?
–> squeaky pop test –> put a lighted splint in the gas - if it creates a squeaky pop sound that gas is hydrogen
why are magnesium with acid reaction faster than zinc with acid
In comparison to the acid reactions with magnesium, the acid reactions with zinc are slower as zinc is lower down the reactivity series in comparison with magnesium
what is a base
Base - something that neutralises an acid
Alkalis are soluble in water, some bases are not.
what colour change happens between copper II oxide and dilute h2so4
Copper (II) Oxide (black powder) reacts with hot dilute sulfuric acid
This creates a copper sulfate solution which is BLUE
all copper solutions are what colour
ALL copper solutions = blue/blue-green solution
are nitrates soluble
All nitrates are soluble
what are the only chlorides that are insoluble
Lead and silver are the only chlorides that are insoluble (L and S both in chLorideS)
which lead compounds are soluble
Other than nitrate, anything lead is insoluble
are carbonates soluble
All carbonates are insoluble
are hydroxides soluble
Most hydroxides are insoluble (calcium is partially)
EXCEPTION TO ALL THE ABOVE IS ammonium, potassium and sodium (APS) is ALWAYS soluble
what can you only mix with cold acids to make salts
When making salts, it is only carbonates and magnesium that you can mix cold acids
what do u add in excess when making magnesium sulfate
When making magnesium sulfate, you add magnesium in excess until it stops reacting
when making salts, what 3 metals cant u add in excess and why
You can’t do this with APS (ammonium, potassium and sodium)
Magnesium is not soluble in water - SO, when you add it to aqueous acid, it only reacts with the acid - hence when all the acid has been reacted with, you see the excess magnesium
HOWEVER, with APS, as they are soluble in water, when you add them to aqueous acid, they react with the acid, HOWEVER, they ALSO dissolve in the water - SO you can’t add just enough metal to neutralise the acid
SO, you mix a solution of the metal with a solution of the acid
how do u figure out how much u need to neutralise
To figure out how much of each solution is needed for complete neutralisation, we use titration
when making sodium sulfate crystals, what indicator do u use
When making sodium sulfate crystals we use methyl orange - red in acidic solutions and yellow in alkaline solutions - orange is neutral
why is copper sulfate blue rather than white
Copper sulfate solution is blue as it contains hydrous copper sulfate
why should u use crystallisation instead of evaporation to obtain blue crystals
In the process of obtaining these blue crystals, you must use crystallisation instead of evaporation as if you let all the water evaporate off, it forms anhydrous copper sulfate which is white
what is the symbol equation for hydrous copper sulfate
The symbol symbol of this is:
CuSO4 (aq) + 5H2O(l) –> CuSO4.H2O(s) (got goes in the middle not the bottom)
Crystalisation reaction for magnesium sulfate:
tell me about ammonium crystals
Ammonium sulfate crystals:
NH3 + H2SO4 –> (NH4)2SO4
Unlike the metal crystals, ammonium sulfate crystals don’t undergo water of crystallisation
To make insoluble salts, you mix two soluble solutions together
For silver chloride (an insoluble salt), you mix silver nitrate and sodium chloride
This is a precipitation
precipitate = a solid formed from a chemical reaction that has liquids or gases
In this reaction, the silver chloride is the precipitate
equation to make silver cchloride
AgNO3(aq)+NaCl(aq–>AqCl(s)+NANO3(aq)
why is silver chloride a precipitate
Ionic compounds dissociate in water (separate). SO, when you mix two aqueous solutions, sometimes a precipitate can form
The attraction between silver ions and chloride ions is so strong that the ions stick together even in water, forming a precipitate
what is an example of precipitation reaction
For silver chloride (an insoluble salt), you mix silver nitrate and sodium chloride
This is a precipitation, In this reaction, the silver chloride is the precipitate
define a precipitate
precipitate = a solid formed from a chemical reaction that has liquids or gases
What is the process of making salts when part ofthe salt is ammonium, potassium or sodium salts?
you mix a metal + an acid
add the metal to the acid until you see unreacted metal residue
filter ou any unreacted metal
heat the solution slowly and the leave to dr
What is the process of making salts when it is NOT an ammonium, potassium, or sodium salt?
mix and acid with an alkali
add an indicator to monitor when the solution has neutralised
when it has neturalised
you then heat the solution until the crystals form and are then left to dry
whats the equation to make barium sulfate
Ba(NO3)2+K2SO4—>BaSO4 + 2KN03
what is arhnius theory
Arrhenius theory = acid produces H+ in solution and alkali produces OH- in solution
what is bronsted-lowry theory
Bronsted-Lowry Theory:
an acid is a proton donor
what is an alkali
Proton = H+ ion
an alkali is a proton doner
H2O + HCl –> H3O+ (aq) + Cl-
