Acids and Bases

Question 1

most common lab acids

Answer 1

HCl, H2SO4, HNO3

Question 2

what makes solutions acidic

Answer 2

when dissolved, all acids form H+ (hydrogen ions) which makes solution acidic

Question 3

common lab alkalis

Answer 3

NaOH, CA(OH)2, NH3

Question 4

what ions do alkalis form when dissolved in water?

Answer 4

(OH)-

Question 5

pH scale in regards to H+ and (OH)- ions

Answer 5

• lower pH= high concentration of H+

- higher pH= higher concentrations of (OH)-

Question 6

indicator for pH scale

Answer 6

universal indicator

Question 7

red litmus/ blue litmus results

Answer 7

red litmus= blue in alkalis/ red in acid

blue litmus= red in acids/ blue in alkalis

Question 8

does litmus paper have to be dry or damp?

Answer 8

damp

Question 9

definition of an acid

Answer 9

a substance that dissolves in water to form hydrogen ions. a proton donor.

Question 10

definition of an alkali

Answer 10

a substance that dissolves in water to form hydroxide ions. a proton receiver/ acceptor.

Question 11

strong acids properties

Answer 11

• react quicker (higher temp rise)
• dissociate fully in water to produce maximum number of hydrogen ions
• good conductors of electricity
• i.e. HCl, HNO3, H2SO4

Question 12

weak acids properties

Answer 12

• react slower (lower temp rise)
• only partially ionise
• poor conductors of electricity
• i.e. ethanoic acid (CH3COOH)

Question 13

strong alkalies properties

Answer 13

• react quicker (higher temp rise)
• dissociate fully in water to produce maximum number of hydroxide ions
• good conductors of electricity
• i.e. NaOH

Question 14

weak alkalies properties

Answer 14

• react slower (lower temp rise)
• only partially ionise
• poor conductors of electricity
• i.e. NH3

Question 15

metal + acid =

Answer 15

metal + acid= salt + H2

Question 16

neutralisation reactions

Answer 16

Metal oxide + acid = salt+ water
Metal hydroxide + acid= salt + water
Aqueous ammonia+ acid= salt + water
Base + acid = salt + water

Question 17

CARBONATE + acid=

Answer 17

CARBONATE + acid= salt + water + CO2

Question 18

AMMONIUM SALTS + alkali=

Answer 18

AMMONIUM SALTS + alkali = metal salt + ammonia + water

Question 19

salt from metal

Answer 19

1. add excess metal (to acid in flask)
2. warm flask gently
3. filter excess metal (filtrate= metal salt)
4. put filtrate into evaporating basin and heat until crystallisation point reached
5. allow salt to crystallise at room temp.
6. filter off crystals and wash w/ little solvent
7. dry crystals between sheets of filter paper

Question 20

salt from insoluble bases

Answer 20

1. add excess base (to acid in flask)
2. warm flask gently
3. filter excess metal (filtrate= metal salt)
4. put filtrate into evaporating basin and heat until crystallisation point reached
5. allow salt to crystallise at room temp.
6. filter off crystals and wash w/ little solvent
7. dry crystals between sheets of filter paper

Question 21

what do u do to make soluble salt ?

Answer 21

TITRATION

Question 22

example of soluble salt equation

Answer 22

potassium hydroxide + sulfuric acid= potassium sufate + water

Question 23

TITRATION METHOD

Answer 23

1. put alkali in flask (with volumetric pipette) with indicator
2. add acid from burette until indicator changes colour to neutral
3. record volume of acid added
4. repeat experiment without indicator
5. put in evaporating basin until crystallisation point reached
6. allow crystals to form, then wash and dry (with filter paper)

Question 24

SOLUBLE SALTS

Answer 24

• all with group 1 elements
• all nitrates
• all ammonium salts
• most chlorides, bromide, iodides
• most sulfates
• group 1 and 2 oxides

Question 25

insoluble salts

Answer 25

• silver and lead chlorides, bromide, iodides
• sulphates of calcium, barium, lead
• most hydroxides and carbonates
• most metal oxides

Question 26

MAKE INSOLUBLE SALT

Answer 26

PRECIPITATION

• add reactants
• filter salt from solution
• wash with distilled water and dry