Acids and bases

Question 1

Arrhenius theory of acids and bases

Answer 1

-acidic substances dissociated in aqueous solution’s produce hydrogen ions.
- basic substance dissociated in aqueous solutions produce hydroxide ions.

Question 2

Bronsted Lowry acid and bases

Answer 2

-acid is a hydrogen ion (proton) donor
-base is a hydrogen ion (proton) acceptor

Question 3

amphiprotic substances

Answer 3

substances are capable of both accepting and donating a proton depending on the reaction conditions. water is amphiprotic.

Question 4

amphoteric substances

Answer 4

a broader term used to describe substances which can react as acids or bases.

Question 5

typical properties of aqueous solutions of acids.

Answer 5

1. in general have a sour taste
2. dissolve many substances
3. change blue plant dye (limtus) to a red colour
4. react with bases to form salts
5. will dissolve in water to form ions and hence, conduct electricity in aqueous solution.
6. Are electrolytes when dissolved in water
7. are molecular in structure.

Question 6

common acids

Answer 6

-hydrogen chloride
- hydrogen nitrite
-hydrogen nitrate
-dihydrogen sulphite
-dihydrogen sulphate
-dihydrogen carbonate
-hydrogen chlorite
-hydrogen chlorate
-dihydrogen phosphate
-ethanoic acid

Question 7

reactions of acids

Answer 7

acid + bases = salt +water
acid +metal = salt +
hydrogen
acid +carbonate = salt + water + carbon dioxide
acid + hydrogen carbonate = salt +water +carbon dioxide

Question 8

typical properties of aqueous solutions of bases

Answer 8

1. in general have a bitter taste
2. feel soapy
3. change red plant dye (litmus) to a blue colour
4. are electrolytes when dissolved or molten, hence, conduct electricity in these states
5. reacts with acids to form salts

Question 9

strong acid

Answer 9

• virtually completley ionise in aqueous solutions
  include: HCl, HNO3, H2SO4

Question 10

Weak acid

Answer 10

partially ionise in solution
-acetic acid (ethanoic acid)
-carbonic acid
-hydrogen carbonate
-if the reaction has a
(⇌) it is a weak acid . as the substance does not completely react with the conjugate base. this is an example of an equilibrium mixture where the solution contains comparable amount of reactants and products.

Question 11

strong base

Answer 11

a strong bases completley accepts a hydrogen ion\
include: OH- and O2-

Question 12

weak bases

Answer 12

partially ionnise in water to produce hydroxide ions,
include: ammonia, ethylamine, and carbonate ion.

Question 13

PH of rain water

Answer 13

5.6

Question 14

PH equation

Answer 14

PH= -log [H3O+]
[H3O+] = 10-ph

Question 15

ionic product constant

Answer 15

Kw= [H3O+] x [OH-} = 10-14 mol^2 dm ^-6 at 25 C

Question 16

acid depostion

Answer 16

a borad term which refers to anhy precipitation from the atmosphere which has a pH less than 5.6, thus rainwater is only classified as acid rain if its pH drops below 5.6

Question 17

wet acid depoistion

Answer 17

-acidified rain, hail, snow, fog, mist

Question 18

Dry acid depoisition

Answer 18

acid producing gases trapped in smoke, ash and other particulates which fall to the ground and form acidic solutions in water.

Question 19

minimise acid depoisition

Answer 19

-due to SO2
pre combustion: removal of sulfur containing contaminants
post combustion: neturalisation of SO2 by reactions with a bases

Question 20

Oxides of nitrogen

Answer 20

-reaction does not occur readily between N and O gas, one natural source is lighting strikes, fossil fueled vehicles and vehicles internal combustion engines.

Question 21

Effects of acid depoisition

Answer 21

• when it trvels throuhg the soil it reacts with the minerals in the ground releasing mg2+, ca2+, and Al3+, in a process called leaching. they travel throuhgb ground water to be deposited to bodies of water. the loss of mg and ca, and the release of Al (toxic) impairs plant growth.

Question 22

reducing sulfur dioxide emissions.
- pre

Answer 22

-large proportion of emissions come from electricity generated using coal. this can be reduced by using coal with a lower sulfur content or crushing and washing coal to remove metal sulphides. also removed from petroleum products through the process of hydrodesulfurization which is a catalytic process which involves the reaction of sulfur with hydrogen gas to form hydrogen sulfur.

Question 23

reducing sulfur dioxide -post

Answer 23

flue-gas desulfurisation- a method used to remove sulfur dioxide from the flue gases from fossil fuels electricity plants. the flue gases are passed through a slurry of calcium carbonate to produce calcium sulfite/

Question 24

reducing oxides of nitrogen emissions

Answer 24

-the addition of catalytic converters to vehicles has significantly reduced the emissions of NO

Question 25

molarity

Answer 25

the concentration of a solution expressed in mol dm^-3

Question 26

burette

Answer 26

used to deliver variable volumes accuratley

Question 27

titre

Answer 27

the volume delivered from the burette

Question 28

volumetric pipette

Answer 28

used for accurate transfer of fixed volumes

Question 29

aliquot

Answer 29

the known volume delivered from the pipette

Question 30

titration

Answer 30

the process of mixing the reactant in a volumetric analysis until they are present in the exact mole ratio represented in the balanced equation for the reaction. this is a procedure for accurately determining the concentration of an unknown solution.

Question 31

standard solution

Answer 31

a solution of accuratley known concentration

Question 32

primary standard

Answer 32

a substance which can be used to make up a standard solution

Question 33

primary standard solution

Answer 33

-usually madde by dissolving an accurately known mass of a primary standard in a volumetric flask

Question 34

primary standard properties

Answer 34

1) be readily available in pure form
2) have a known formula
3) be easy to store without deteriorating or reacting with the atmosphere.