7 Acids, bases and salts

Question 1

metal + acid

Answer 1

salt + hydrogen

Question 2

base + acid

Answer 2

salt + water

Question 3

metal oxide + acid

Answer 3

salt + water

Question 4

metal hydroxide + acid

Answer 4

salt + water

Question 5

metal carbonate + acid

Answer 5

salt + water + carbon dioxide

Question 6

base + ammonium salts

Answer 6

salt + ammonia gas + water

Question 7

red litmus

Answer 7

turns blue in alkali, stays red in acids

Question 8

thymolphthalein

Answer 8

blue in alkalis and colourless in acid

Question 9

methyl orange

Answer 9

yellow in alkalis and red in acids

Question 10

bases examples

Answer 10

metal oxides and hydroxides

Question 11

alkalis

Answer 11

soluble bases

Question 12

aqueous solutions of acids contain what

Answer 12

H+ ions

Question 13

aqueous solutions of alkalis contain what

Answer 13

OH- ions

Question 14

another name for hydrogen ion

Answer 14

a proton (H+)

Question 15

neutralisation reaction between an acid and an alkali

Answer 15

H+ + OH- –> H2O

Question 16

proton donors

Answer 16

acids

Question 17

proton acceptors

Answer 17

bases

Question 18

strong acid

Answer 18

an acid that is completely dissociatie in aqueous solution

Question 19

weak acid

Answer 19

an acid that is partially dissociated in aqueous solution

Question 20

acid dissociation

Answer 20

the acid turns into hydrogen ions and anions in an aqueous solution

Question 21

Show how hydrochloric acid is a strong acid

Answer 21

HCl(aq) → H+(aq) + Cl– (aq)

Question 22

Show how ethanoic acid is a weak acid

Answer 22

CH3COOH(aq) ⇌ H+ (aq) + CH3COO– (aq)

Question 23

Are oxides acidic or basic

Answer 23

Metals form oxides that are basic , but non-metals form oxides that are acidic

Question 24

amphoteric oxides

Answer 24

oxides that react with acids and with bases to produce a salt and water

Question 25

examples of amphoteric oxides

Answer 25

Al2O3 and ZnO

Question 26

hydrated substance

Answer 26

substance that is chemically combined with water

Question 27

anhydrous

Answer 27

a substance containing no water

Question 28

Preparing soluble salts - adding acid to a solid metal, insoluble base or insoluble carbonate

Answer 28

1. Heat acid until warm, then add metal/base/carbonate, stirring constantly until it stops disappearing
2. Filter mixture to remove excess base, transfer solution to evaporatiing basin.
3. heat solution to evaporate water and make the solution saturated.
4. Leave the filtrate in a warm place to dry and crystalise
5. Decant excess solution and allow crystals ot dry or blot to dry with filter paper

Question 29

Preparing soluble salts - reacting a dilute acid and alkali

Answer 29

1. Add alkali + indicator to conical flask using a pipette
2. Add acid to burette, noting the starting volume
3. Add acid to alkali slowly until indicator changes colour. calculate vol of acid added. Repeat steps 1-3 without indicator.
4. Transfer solution to an evaporating basin, heat to partially evaporate water
5. remove evaporating basin from heat and allow filtrate to dry and crystalise

Question 30

precipitation reaction

Answer 30

• reacting two soluble salts together to form an insoluble salt
• double displacement reaction (two metals swap the chemical they’re bonded to)

Question 31

Preparation of precipitation reaction

Answer 31

1. Dissolve soluble salts in water and mix together using a stirring rod in a beaker
2. Filter to remove precipitate from mixture
3. Wash residue with distilled water to remove traces of other solutions
4. Leave in an oven to dry (or just leave to dry)

Question 32

water of crystalliastion

Answer 32

the water molecules present in hydrated crystals including CuSO4.5H2O and CoCl2.6H2O