Making Salts Flashcards
knowledge recall - 1.1 is a weak area for me
(EQ) Complete the word equation for the reaction.
copper carbonate + sulfuric acid= —– + —– + carbon dioxide
copper sulfate + water
(EQ) name equipment that can be used to warm filtrate gently
- water bath
- electric heater
(EQ) some salts can be produced by reacting sulfuric acid with a metal. Neither copper nor sodium is used to produce a salt with sulfuric acid. Give one reason why each metal is not used.
Copper - unreactive/ low on the reactivity series
Sodium - could explode or get too hot as it is very reactive
Acids will react with reactive metals to make…
a salt and hydrogen
test for hydrogen
burning splint - if hydrogen is present there will be a squeaky pop
what does hydrogen cause during an acid and reactive metal reaction?
bubbling
what is the general rule when a metal is more reactive?
the more reactive the metal, the faster the reaction
how is the general rule “the more reactive the metal, the faster the reaction” indicated?
more bubbles being given off per second from the metals with higher reactivity
put these 4 metals in order of reactivity (highest to lowest)
Aluminium, Copper, Iron, Zinc
aluminium is the most reactive of the four metals, followed by zinc, then iron and finally, copper
Is the reaction of metals with acids exothermic or endothermic?
exothermic (heat energy is given out)
What happens when
acids react with metal hydroxides (alkalis)?
a salt and water are made
nitric acid + lithium hydroxide =
lithium nitrate + water
Is the reaction of metal hydroxides with acids exothermic or endothermic?
exothermic (heat energy is given out)
what is the ionic equation of a metal hydroxide and an acid ?
H+(aq) + OH–(aq) → H2O(l)
what happens when acids react with a base?
a salt and water are made
nitric acid + magnesium oxide =
magnesium nitrate + water
Is the reaction of metal oxides with acids exothermic or endothermic?
exothermic (heat energy is given out)
What happens when acids react with carbonates?
a salt, water and carbon dioxide are made
Name an example of a carbonate and where it is found
calcium carbonate (found in chalk, limestone and marble)
What is the test for carbon dioxide?
passing the gas through limewater, which will go cloudy.
what does carbon dioxide cause during an acid and metal carbonate reaction?
fizzing
Is the reaction of metal carbonates with acids exothermic or endothermic?
exothermic (heat energy is given out)
What 2 things can an acid and metal carbonate reaction be used to test?
- can be used to test unknown solutions to see if they are acidic. - Simply add a solution of sodium carbonate to the solution and if carbon dioxide gas is given off, the solution is acidic.
- can also be used to test unknown solutions for the presence of carbonate (CO3–) ions.
- Simply add an acid to the solution and if bubbles of carbon dioxide are given off, the solution contains carbonate ions.
what is a salt?
A salt is any compound formed by the neutralisation of an acid by a base
where does the name of a salt come from?
The first part comes from the metal, metal oxide or metal carbonate. The second part comes from the acid.
nitric acid always produces salts that end in…
nitrate and contain the nitrate ion, NO3–
hydrochloric acid always produces salts that end in..
chloride and contain the chloride ion, Cl–
sulfuric acid always produces salts that end in
sulfate and contain the sulfate ion, SO42–
If potassium oxide reacts with sulfuric acid what would the products be?
potassium sulfate and water
What does Ammonia form and give an example
Ammonia forms ammonium salts when it reacts with acids. For instance, ammonia reacts with hydrochloric acid to make ammonium chloride.
SALTS (RP 1) METHOD
1) add the metal oxide or carbonate to a warm solution of acid (in a beaker) until no more will react.
2) filter excess metal oxide or carbonate (using filter paper) to leave a solution of the salt.
3) gently warm the salt solution (using an evaporating basin and a Bunsen burner) so that the water evaporates and crystals of salt are formed.
4) leave the solution to cool and crystallise
SALTS (RP 1) HAZARDS AND RISKS
- corrosive acid can cause damage to eyes, so eye protection must be used.
- hot equipment can cause burns, so care must be taken when the salt solution is warmed.
how can soluble salts be made?
soluble salts can be made by reacting acids with insoluble bases, such as metal oxides, metal hydroxides and metal carbonates.
SALTS (RP 1) what equipment can be used in this experiment?
- filter paper
- filter funnel
- beaker
- evaporating basin
- Bunsen burner
what is evaporation?
The process in which a liquid changes state and turns into a gas
SALTS (RP 1) How can you get larger crystals?
You get larger crystals if you evaporate the water slowly.
what is titration?
A quantitative procedure in which two solutions react in a known ratio, so if the concentration of one solution is known and the volumes of both are measured, the concentration of the other solution can be determined
when is a titration used to produce a salt?
when reacting an acid with an alkali
(USING A TITRATION TO MAKE A SALT) what equipment can be used in this experiment?
- a pipette to accurately measure a certain volume of acid or alkali
- a pipette filler to use the pipette safely
- a conical flask to contain the liquid from the pipette
- a burette to add small, measured volumes of one reactant to the other reactant in the conical flask
(USING A TITRATION TO MAKE A SALT) method
1) Use the pipette and pipette filler to add 25 cm3 of alkali to a clean conical flask.
2)Add a few drops of indicator and put the conical flask on a white tile.
3) Fill the burette with acid and note the starting volume.
4) Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
5) Stop adding the acid when the end-point is reached (the appropriate colour change in the indicator happens). Note the final volume reading.
6) Repeat steps one to five using the same volume of acid from the burette without using an indicator. The resulting solution can then be evaporated to obtain pure crystals of the salt.
how do you make an insoluble salt?
To make an insoluble salt, two
soluble salts need to react together in a precipitation reaction
what is a precipitation reaction?
A reaction in which an insoluble solid is formed when certain solutions are mixed
what does insoluble mean?
Unable to dissolve in a particular solvent
what does soluble mean?
Able to dissolve in solvent
examples of soluble salts:
- All nitrates
- All common sodium, potassium and ammonium salts
- Most common sulfates
- Most common chlorides
- Lithium, sodium, potassium and ammonium carbonates
examples of insoluble salts:
- Calcium sulfate and barium sulfate
- Silver chloride
- Most common carbonates
how is silver chloride made?
by reacting a soluble silver salt with a soluble chloride salt
what is suspension?
A mixture of two substances, one of which is finely divided throughout the other
what is a precipitate?
A suspension of particles in a liquid formed when a dissolved substance reacts to form an insoluble substance, eg in a precipitation reaction
what is an ionic equation?
a chemical equation in which the electrolytes in aqueous solution are expressed as dissociated ions
