Chapter 7

Question 1

Indicators: universal indicator

Answer 1

Changes colour to match pH scale (depending on pH of solution)

Question 2

Indicators: litmus indicator

Answer 2

• red in acidic solutions
• purple in neutral solutions
• blue in alkaline solutions

Question 3

Indicators: litmus paper

Answer 3

• Red litmus paper -> turns blue in alkaline solutioms
• Blue litmus paper -> turns red in acidic solutions

Question 4

Indicators: methyl orange

Answer 4

• Red in acidic solutions
• Yellow in alkaline solutions

Question 5

Indicators: thymolphthalein

Answer 5

• Colourless in acidic soloutions
• Blue in alkaline solutions

Question 6

Acid

Answer 6

H+ donor/proton donor

Question 7

Base

Answer 7

H+ receiver/ proton acceptor

Question 8

Alkali

Answer 8

Base that is soluble in water

Question 9

Neutralisation

Answer 9

Reaction between an acid and a base/alkali -> products are neutral

Question 10

Aqueous solutions of acids (neutralisation)

Answer 10

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 -

Question 11

Aqueous solutions of alkalis (neutralisation)

Answer 11

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-

Question 12

Acid + base

Answer 12

Acid + base (metal oxide or hydroxides) -> salt (sulfates, nitrates or chlorides) + water

Question 13

Acid + ammonia

Answer 13

Acid + ammonia -> ammonium salt

Question 14

Acid + metal

Answer 14

Acid + metal -> salt + hydrogen

Question 15

Acid + metal carbonate

Answer 15

Acid + metal carbonate -> salt + water + carbon dioxide

Question 16

Base + ammonium salt

Answer 16

Base + ammonium salt -> salt + water + ammonia

Question 17

Types of oxides: acidic

Answer 17

• react with bases
• are non-metal oxides
  -> on right side of periodic table
  Eg: SO2 and CO2

Question 18

Types of oxides: basic

Answer 18

• react with acids
• are metal oxides
  -> on left side of periodic table
  Eg: CaO and CuO

Question 19

Types of oxides: amphoteric

Answer 19

• 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

Question 20

Strong acids

Answer 20

Acid that is completely ionised (dissociated) in aqueous solution -> releasing lots of H+ ions

Question 21

Weak acid

Answer 21

Acid that is partially ionised (dissociated) in aqueous solution -> releasing fewer H+ ions

Question 22

Soluble or inssoluble salts: sodium, potassium and ammonium

Answer 22

Soluble: ALL
Insoluble: NONE

Question 23

Soluble or inssoluble salts: nitrates

Answer 23

Soluble: ALL
Insoluble: NONE

Question 24

Soluble or inssoluble salts: Ethanoates

Answer 24

Soluble: ALL
Insoluble: NONE

Question 25

Soluble or inssoluble salts: chlorides

Answer 25

Soluble: MOST ARE Insoluble: SILVER AND LEAD (II)

Question 26

Soluble or inssoluble salts: sulphates

Answer 26

Soluble: MOST ARE Insoluble: BARIUM, CALCIUM AND LEAD (II)

Question 27

Soluble or inssoluble salts: carbonates

Answer 27

Soluble: CARBONATES OF SODIUM, POTASSIUM AND AMMONIUM Insoulble: MOST ARE

Question 28

Soluble or inssoluble salts: hydroxides

Answer 28

Soluble: HYDROXIDES OF SODIUM, POTASSIUM AND CALCIUM (calcium is slightly soluble) Insoluble: MOST ARE

Question 29

Preperation of salts: soluble salt from acid and soluble base -> alkali

Answer 29

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

Question 30

Preperation of salts: soluble salt from acid and insoluble base

Answer 30

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

Question 31

Preperation of salts: Insoluble salt from two soluble salts

Answer 31

1) mix two solutions 2) filter to remove insoluble salt 3) wash to remove impurities 4) leave to dry on filter paper

Question 32

Preperation of salts: soluble salt from acid and soluble base/alkali -> recognising reactants

Answer 32

Sodium hydroxide Potassium hydroxide Ammonium hydroxide

Question 33

Preperation of salts: soluble salt from acid and soluble base/alkali: how is endpoint determined? -> how much base is needed to neutralise

Answer 33

- Acids are aqueous - Soluble bases are aquaeous - Use titration to find point of neutralisation

Question 34

Preperation of salts: soluble salt from acid and soluble alkali/bass -> common example

Answer 34

Potassium hydroxide + hydrochloric acid -> potassium chloride + water

Question 35

Preperation of salts: soluble salt from acid and insoluble base: recognising reactants

Answer 35

Insoluble bases Eg: metal oxides -> copper oxide, calcium oxide OR copper carbonate

Question 36

Preperation of salts: soluble salt from acid and insoluble base: how is endpoint determined? -> how much base is needed to neutralise

Answer 36

- Acids are aquaeous - Insoluble bases are solid - Add an excess of the solid -> add until no more solid dissolve in acid

Question 37

Preperation of salts: soluble salt from acid and insoluble base:common example

Answer 37

Sulfuric acid + copper oxide -> copper sulfate + water

Question 38

Preperation of salts: Insoluble salt from two soluble salts -> recognising reactants

Answer 38

NO MENTION OF AN ACID REACTANT - All reactants are salts: -> metal sulfate, metal nitrate, metal chloride, metal hydroxide, metal carbonate

Question 39

Preperation of salts: Insoluble salt from two soluble salts -> common example

Answer 39

Barium nitrate + sodium sulfate -> sodium nitrate +barium sulfate - Insoluble substance -> salt wanted