Acids, alkalis, and salts Flashcards
What two substances have a pH of 1?
Car battery acid and stomach acid
What substances have a pH of 3 (2 of them), 4, 5?
Lemon juice and vinegar, acid rain, normal rain
What substances have a pH of 8, 10, 11, 12, 13?
Washing up liquid, pancreatic juice, soap powder, bleach, caustic soda drain cleaner.
What do you use to test pH?
Indicator
What is an acid? What do they form in water?
A substance with a pH of less than 7, H+ ions in water
What is an BASE?
A substance with a pH grater than 7
What is an alkali? What happens when in water?
A BASE that dissolves in water. They form OH- ions in water.
What do H+ ions do to solutions, and OH-?
Make solutions acidic, make solutions alkaline.
What is the reaction between acids and bases called?
What state are the products in (pH), what can be used to show this?
Neutralisation
Neutral, Universal Indicator
What is the word equation for a neutralisation reaction?
Acid + BASE = Salt + water
What is the word symbol for a neutralisation reaction?
H+ + OH- = H2O (aq) (aq) (l)
What does... stand for? S L Aq G
Solid
Liquid
Aqueous
Gas
Write the word equation for a metal and acid reacting…
Acid + Metal = Salt + hydrogen
The more reactive the metal the…
faster the reaction will go.
The name of the slat produced depends on…
which acid is used.
What salt will hydrochloric acid always produce?
2HCl + Mg =
6HCl + 2Al =
2HCl + Zn =
Chloride salts…
MgCl2 + H2 Magnesium chloride
2AlCl3 + 3H2 Aluminium Chloride
ZnCl2 + H2 Zinc Chloride
What salt will sulfuric acid acid always produce?
H2SO4 + Mg =
3H2SO4 + 2Al =
H2SO4 + Zn =
Sulfate salts…
MgSO4 + H2 Magnesium Sulphate
Al2(SO4)3 + 3H2 Aluminium Sulphate
ZnSO4 + H2 Zinc sulphate
Nitric acid produces…
but it reacts with….. to produce …. instead.
Nitrates
metals to produce nitrogen oxides
Metal oxides and hydroxides are…
BASES
Some Metal oxides and hydroxides do what in water?
Dissolve
The Metal oxides and hydroxides that dissolve in water are called what?
Alkalis
Bases that don’t dissolve in water still…
react with acid
So all Metal oxides and hydroxides react with … to get…
Write the word equations for these…
acid + metal oxide =
acid + metal hydroxide =
Acid to get salt and water.
Salt + water
Salt + water
What type of reaction is acid + Metal oxide or hydroxide
Neutralisation
What decides what salt you get when neutralising Metal oxides and hydroxides
e.g
Hydrochloric acid + copper oxide =
The metal and acid
Copper chloride and water
What can ammonia be neutralised with to make a good fertiliser?
HNO3, Nitric acid
What is the formula for ammonia
NH3
What does ammonia dissolve into in water?
An alkaline solution
When ammonia’s alkaline solution reacts with …. you get a …. called…
Nitric acid you get a neutral salt called ammonium nitrate
What is he symbol and word equation for the neutralisation of ammonia?
What is not produced that normally is in a neutralisation reaction?
NH3 + HNO3 = NH4NO3 (aq all the way through)
ammonia + nitric acid = ammonium nitrate
Water
Why is ammonium nitrate a good fertiliser?
It has two sources of nitrogen, the ammonia and nitric acid, a double dose, and plants need this to make proteins.
Most oxides and hydroxides are….. in water.
Insoluble
Making soluble salts from a metal or insoluble base:
- Pick a metal or … and the right acid for the salt you want
- Add the two together, the …. will dissolve in the .. as it reacts.
- You will know when all the acid has been …. because the excess … will ….. .
- Then………. the excess metal or ………… or……. to get the salt solution.
- To get……… of salt evaporate some of the ….. to make the solution more……… the leave the rest to ……. very slowly, this is called ……………
- an insoluble base, metal hydroxide or oxide
- solid in the acid
- neutralised …. metal or metal oxide/hydroxide will sink to the bottom of the flask.
- filter… oxide or hydroxide
- pure solid crystals of salt…. water… concentrated… evaporate … Crystallisation.
Making soluble salts using an alkali.. a BASE that dissolves in water:
- Add exactly the right amount of… to … the acid
- Use … to check if the solution is fully….
- Then … the experiment so that the products aren’t … with indicator
- Then… the water to … the salt as normal
- alkali, neutralise
- Universal indicator … neutralised
- repeat…. contaminated
- The evaporate off the water to crystallise
Why can’t you use crystallisation using an alkali?
You can’t see when the reaction’s finished because you can’t just add excess solid to neutralise all the acid.
Making insoluble salts…
- Pick two …. containing the …. you need
- For example to make lead chloride mix lead nitrate … with … ions, for example mix ….. with …..
- As the salt is …. it will ….. out to the bottom of the flask
- You then…… it from the …. , .. it and dry it on … paper
Precipitation reactions
- solutions … ions
- …ions with chloride ions, for example mix lead nitrate solution with.. sodium chloride solution.
- insoluble… precipitate out…
- filter it from the solution, wash it dry it on filter paper.
How many experiments are there for making salts? What are they?
Making … salts from….
3
Soluble salts from an insoluble base (or metal)
Soluble slats from an alkali
Insoluble salts using two solutions containing the wanted ions.
What can precipitation reactions be used for?
Water (2)
Waste
Removing poisonous ions from drinking water (lead).
Magnesium and calcium can be removed, they make water “hard”, stopping soap lathering properly,
Treating effluent (sewage) removing unwanted ions.
