Acids, Bases and Salts

Question 1

what is an acid?

Answer 1

a substance that can donate a proton to another substance

Question 2

what is a base?

Answer 2

a substance that can accept a proton from another substance

Question 3

what are alkali?

Answer 3

soluble bases that produce hydroxides in water

Question 4

what are some common strong and weak acids?

Answer 4

strong acids:
- hydrochloric acid
- sulfuric acid
- nitric acid
weak acids:
- phosphoric acid
- carbonic acid
- ethanoic acid (CH3COOH)

Question 5

what are some common strong and weak alkali?

Answer 5

strong alkali:
- sodium hydroxide
- potassium hydroxide
- calcium hydroxide (limewater)
weak alkali:
- aqueous ammonia (NH3)

Question 6

definition of a strong acid?

Answer 6

acid that dissociates fully in solution to give protons

Question 7

definition of a weak acid?

Answer 7

acid that dissociates partially in solution to give protons

Question 8

definition of a strong base?

Answer 8

base that dissociates fully to give hydroxide ions

Question 9

definition of a weak base?

Answer 9

base that dissociates partially to give hydroxide ions

Question 10

what is the strength of an acid?

Answer 10

the extent of dissociation of the acid in solution

Question 11

what is the concentration of an acid?

Answer 11

the number of moles per unit volume of acid initially put in the solution before dissociation takes place

Question 12

what is the definition of pH?

Answer 12

negative logarithm to the base 10 of the concentration of hydrogen ions in solution in mol dm-3

Question 13

colors of the universal indicator at 25 degrees celsius?

Answer 13

red: 0-2
orange: 3-4
yellow: 5-6
green: 7
blue-green: 8-10
blue: 11-12
violet: 13-14

Question 14

chemical equation for the Haber Process?

Answer 14

N2 (g) + 3H2 (g) <-> 2NH3 (g)

Question 15

operating conditions for the Haber Process?

Answer 15

• high pressure of 250 atm
• temperature at 450 degrees celsius
• iron catalyst
• mole ratio of N2:H2 is 1:3

Question 16

elements in which group give what type of oxides?

Answer 16

basic oxides: groups 1 and 2, groups of metal elements
acidic oxides: groups 14, 15 and 16, groups of non-metal elements

Question 17

what makes amphoteric and neutral bases special?

Answer 17

• amphoteric bases react with both acid and bases but do not react with water
• neutral bases do not react with acids nor bases

Question 18

chemical equation of silicon dioxide reacting with molten hot sodium hydroxide?

Answer 18

SiO2 (s) + molten NaOH (l) (350 degrees celsius)-> Na2SiO3 (l) + H2O (g)

Question 19

chemical equation of aluminium oxide reacting with a base? (*)

Answer 19

Al2O3 + 2NaOH + 3H2O -> 2NaAl(OH)4

Question 20

chemical equation of aluminium oxide reacting with an acid?

Answer 20

Al2O3 + 6HCl -> 2AlCl3 + 3H2O

Question 21

examples of amphoteric oxides?

Answer 21

• aluminium oxide
• lead(II) oxide
• zinc oxide

Question 22

examples of neutral oxides?

Answer 22

• carbon monoxide (CO)
• water (H2O)
• nitric oxide (NO)
• nitrous oxide (N2O)

Question 23

salts with what cations are always soluble in water?

Answer 23

• group 1 cation
• ammonium

Question 24

salts with what anions are always soluble in water?

Answer 24

nitrate anion

Question 25

halide (other than fluorine) salts are all soluble in water except for..?

Answer 25

1. lead(II) halide 2. silver halide

Question 26

sulfate salts are all soluble in water except for..?

Answer 26

1. calcium sulfate 2. lead(II) sulfate 3. barium sulfate

Question 27

carbonate salts, oxides and hydroxides are all insoluble in water except for salts with..?

Answer 27

- group 1 cation - ammonium

Question 28

process of neutralization?

Answer 28

acid + base -> salt + water

Question 29

process of acid-metal reaction?

Answer 29

metal + acid -> salt + hydrogen gas

Question 30

process of acid-carbonate reaction?

Answer 30

carbonate + acid -> salt + water + carbon dioxide

Question 31

what metals to avoid using for acid-metal reactions and why?

Answer 31

- group 1 metals as they react very violently - copper, silver and gold metals as they are not reactive at all

Question 32

process of acid-ammonia reaction?

Answer 32

acid + ammonia -> ammonium salt

Question 33

chemical equation of an ammonium salt with a base?

Answer 33

ammonium salt + base (warm)-> salt + water + ammonia gas