Chapter 7 Flashcards
Indicators: universal indicator
Changes colour to match pH scale (depending on pH of solution)
Indicators: litmus indicator
- red in acidic solutions
- purple in neutral solutions
- blue in alkaline solutions
Indicators: litmus paper
- Red litmus paper -> turns blue in alkaline solutioms
- Blue litmus paper -> turns red in acidic solutions
Indicators: methyl orange
- Red in acidic solutions
- Yellow in alkaline solutions
Indicators: thymolphthalein
- Colourless in acidic soloutions
- Blue in alkaline solutions
Acid
H+ donor/proton donor
Base
H+ receiver/ proton acceptor
Alkali
Base that is soluble in water
Neutralisation
Reaction between an acid and a base/alkali -> products are neutral
Aqueous solutions of acids (neutralisation)
Contain H+ ions -> this is because acids ionise (split up) in solution to produce a hydrogen ion, H+, and another ion
Eg: HCl -> H+ + Cl -
Aqueous solutions of alkalis (neutralisation)
Contain OH- ions -> this is because acids ionise (split up) in solution to produce a hydroxide ion, OH- and another ion
Eg: NaOH -> Na+ + OH-
Acid + base
Acid + base (metal oxide or hydroxides) -> salt (sulfates, nitrates or chlorides) + water
Acid + ammonia
Acid + ammonia -> ammonium salt
Acid + metal
Acid + metal -> salt + hydrogen
Acid + metal carbonate
Acid + metal carbonate -> salt + water + carbon dioxide
Base + ammonium salt
Base + ammonium salt -> salt + water + ammonia
Types of oxides: acidic
- react with bases
- are non-metal oxides
-> on right side of periodic table
Eg: SO2 and CO2
Types of oxides: basic
- react with acids
- are metal oxides
-> on left side of periodic table
Eg: CaO and CuO
Types of oxides: amphoteric
- reacts with bothe acids and bases to form salt and water
- only zin oxide (ZnO) and aluminium oxide (Al2O3)
- experiment: to prove amphoteric add ZnO to acid and base
-> should dissolve in both
Strong acids
Acid that is completely ionised (dissociated) in aqueous solution -> releasing lots of H+ ions
Weak acid
Acid that is partially ionised (dissociated) in aqueous solution -> releasing fewer H+ ions
Soluble or inssoluble salts: sodium, potassium and ammonium
Soluble: ALL
Insoluble: NONE
Soluble or inssoluble salts: nitrates
Soluble: ALL
Insoluble: NONE
Soluble or inssoluble salts: Ethanoates
Soluble: ALL
Insoluble: NONE
Soluble or inssoluble salts: chlorides
Soluble: MOST ARE
Insoluble: SILVER AND LEAD (II)
Soluble or inssoluble salts: sulphates
Soluble: MOST ARE
Insoluble: BARIUM, CALCIUM AND LEAD (II)
Soluble or inssoluble salts: carbonates
Soluble: CARBONATES OF SODIUM, POTASSIUM AND AMMONIUM
Insoulble: MOST ARE
Soluble or inssoluble salts: hydroxides
Soluble: HYDROXIDES OF SODIUM, POTASSIUM AND CALCIUM (calcium is slightly soluble)
Insoluble: MOST ARE
Preperation of salts: soluble salt from acid and soluble base -> alkali
1) Titration using methyl orange to find end point of reaction
2) repeat titration without methyl orange
3) heat until point of crystallisation
4) leave to dry between filter paper
Preperation of salts: soluble salt from acid and insoluble base
1) Heat the acid
2) Add an excess of insoluble base
3) Filtration to remove unreleased base
4) Heat until point of crystallisation
5) Leave to dry between filter paper
Preperation of salts: Insoluble salt from two soluble salts
1) mix two solutions
2) filter to remove insoluble salt
3) wash to remove impurities
4) leave to dry on filter paper
Preperation of salts: soluble salt from acid and soluble base/alkali -> recognising reactants
Sodium hydroxide
Potassium hydroxide
Ammonium hydroxide
Preperation of salts: soluble salt from acid and soluble base/alkali: how is endpoint determined? -> how much base is needed to neutralise
- Acids are aqueous
- Soluble bases are aquaeous
- Use titration to find point of neutralisation
Preperation of salts: soluble salt from acid and soluble alkali/bass -> common example
Potassium hydroxide + hydrochloric acid -> potassium chloride + water
Preperation of salts: soluble salt from acid and insoluble base: recognising reactants
Insoluble bases
Eg: metal oxides
-> copper oxide, calcium oxide OR copper carbonate
Preperation of salts: soluble salt from acid and insoluble base: how is endpoint determined? -> how much base is needed to neutralise
- Acids are aquaeous
- Insoluble bases are solid
- Add an excess of the solid -> add until no more solid dissolve in acid
Preperation of salts: soluble salt from acid and insoluble base:common example
Sulfuric acid + copper oxide -> copper sulfate + water
Preperation of salts: Insoluble salt from two soluble salts -> recognising reactants
NO MENTION OF AN ACID REACTANT
- All reactants are salts:
-> metal sulfate, metal nitrate, metal chloride, metal hydroxide, metal carbonate
Preperation of salts: Insoluble salt from two soluble salts -> common example
Barium nitrate + sodium sulfate -> sodium nitrate +barium sulfate
- Insoluble substance -> salt wanted
