ACIDS, BASES AND SALTS 2B

Question 1

Definition of an acid

Answer 1

Proton donor - releases H+ ions when in aqueous solution

Question 2

Definition of a strong and weak acid

Answer 2

Strong is fully dissociated in solution

Weak is partially dissociated in solution

Question 3

What is the link between strength of acids and the concentration of H+ ions?

Answer 3

The weaker the acid is, the lower proportion of the acid is dissociated, and so there is a lower concentration of H+ ions in the solution.

Question 4

How is a strong acid generally written?

Answer 4

HA(aq) -> H(aq)+ + A(aq)-

Question 5

How is a weak acid generally written?

Answer 5

HA(aq) EQUILIBRIUM ARROWS H(aq)+ + A(aq)-

Question 6

Definition of a base

Answer 6

Proton acceptor

Question 7

Name the types of bases and how they are bases

Answer 7

Metal hydroxides - accepts H+ to become water
Metal oxides - accepts H+ to become OH- (soluble oxide)
- accepts 2H+ to become water
Ammonia/amino compounds - N forms a dative bond with H+ ion

Question 8

How can water act as a base?

Answer 8

H+ +H2O -> H3O+ (hydronium ion)

Question 9

How can water act as an acid?

Answer 9

H2O -> OH- + H+

Question 10

Definition of an alkali

Answer 10

Soluble base that releases OH- ions in water

Question 11

Definition of a salt

Answer 11

Ionic compounds formed when the H+ ions in acids are replaced by metal ions or ammonium ions

Question 12

Acid + Metal hydroxide

Answer 12

Salt + Water

Question 13

Acid + Metal oxide

Answer 13

Salt + Water

Question 14

Acid + Metal carbonate

Answer 14

Salt + Water + Carbon dioxide

Question 15

Acid + reactive metal

Answer 15

Salt + Hydrogen

Question 16

Why do ionic compounds have high melting and boiling points?

Answer 16

A lot of energy is needed to break the strong electrostatic forces of attraction between oppositely charged ions.

Question 17

Why do ionic compounds conduct electricity when molten or in aqueous solution?

Answer 17

When molten, ions are free to move as mobile charge carriers.

Question 18

Why do ionic compounds dissolve in polar solvents?

Answer 18

Polar molecules break down the lattice structure and surround the ions in solution. If the compound has larger charges, they are less soluble.

Question 19

Why are ionic compounds hard crystalline substances?

Answer 19

Made up of ions that are strongly attracted to each other by electrostatic forces

Question 20

Soluble or insoluble - K

Answer 20

Soluble

Question 21

Soluble or insoluble - Na

Answer 21

Soluble

Question 22

Soluble or insoluble - NH4+

Answer 22

Soluble

Question 23

Soluble or insoluble - Halides

Answer 23

Soluble except when combined with Ag+,Pb2+,Hg+

Question 24

Soluble or insoluble - Nitrates

Answer 24

Soluble

Question 25

Soluble or insoluble - Sulfates

Answer 25

Soluble except when combined with Ag+,Pb2+,Ca2+,Sr2+,Ba2+

Question 26

Soluble or insoluble - Carbonates

Answer 26

Insoluble except when combined with Na, K, NH4+

Question 27

Soluble or insoluble - Oxides

Answer 27

Insoluble except when combined with Group 1 or NH4+

Question 28

Soluble or insoluble - Phosphates

Answer 28

Insoluble except when combined with Group 1 or NH4+

Question 29

Soluble or insoluble - Hydroxides

Answer 29

Insoluble except when combined with Group 1 or NH4+, Ca2+, Mg2+, Sr2+, Ba2+

Question 30

Soluble or insoluble - Sulfides

Answer 30

Insoluble except when combined with Group 1 or NH4+

Question 31

Soluble or insoluble - Chromates

Answer 31

Insoluble except when combined with Group 1 or NH4+, Ca2+, Mg2+

Question 32

Acid + Metal hydrogen carbonate

Answer 32

Salt + Water + Carbon dioxide

Question 33

Acid + Alkali

Answer 33

Salt + Water

Question 34

Test for halides (including in isolation)

Answer 34

Add silver nitrate to unknown substance Cl ion = white precipitate Br ion = cream precipitate I ion = yellow precipitate In isolation add dilute ammonia solution -> precipitate dissolves then it's Cl ions Add conc. ammonia solution -> dissolves then it's Br ions Doesn't dissolve in either then it's I ions

Question 35

What are the ions that don't change in a reaction called?

Answer 35

Spectator ions

Question 36

What must ionic equations balance for?

Answer 36

Atoms and charge

Question 37

Test for sulfates

Answer 37

Add Barium chloride and if a white precipitate forms then it's a sulfate

Question 38

Test for carbonates

Answer 38

Add dilute nitric acid and there should be effervescence. | To prove this is CO2, bubble it through limewater and it will turn cloudy

Question 39

Test for ammonium ions

Answer 39

Add sodium hydroxide solution and heat. Hold damp red litmus paper over it and it will turn blue if ammonium ions are present