salts

Question 1

definition of salts

Answer 1

is an ionic compound when the hydrogen ion of an acid is replaced by a metal ion or ammonium ion

Question 2

what are the reactions of acid

Answer 2

acid + metal
acid + carbonate
acid + base

Question 3

acid + metal =

Answer 3

salt + hydrogen gas

Question 4

acid + carbonate =

Answer 4

salt + carbon dioxide + water

Question 5

acid + base =

Answer 5

salt + water

Question 6

base are recognised by

Answer 6

oxides or hydroxides

Question 7

how to name the salts?

Answer 7

take the M/B/S name + metal (ends with ‘ate’ ‘ide’ etc)

Question 8

SPAN are… salts

Answer 8

soluble

Question 9

all carbonates are… salts. except…

Answer 9

insoluble

sodium, potassium and ammonium

Question 10

all chlorides are… salts. except…

Answer 10

soluble

lead (ll) and silver

Question 11

all sulfates are… salts. except…

Answer 11

soluble

calcium, lead and barium

Question 12

all metal oxides and hydroxides are… . except

Answer 12

insoluble

Sodium Potassium Calcium Ammonium

Question 13

what are the 3 methods of salt preparation

Answer 13

crystallisation
titration
precipitation

Question 14

the equation of crystallisation

Answer 14

(s) + (aq) = (aq)

Question 15

the equation of titration

Answer 15

(aq) + (aq) = (aq)

Question 16

the equation of precipitation

Answer 16

(aq) + (aq) = (s)

Question 17

which method(s) produce soluble salts

Answer 17

titration and crystallisation

Question 18

which method(s) produce insoluble salts

Answer 18

precipitation

Question 19

which method(s) use acid reactions and which method(s) don’t?

Answer 19

titration and crystallisation uses acid reactions

precipitation do not use acid reactions

Question 20

what are the 3 common acids

Answer 20

hydrochloric acid
nitric acid
sulfuric acid

Question 21

chemical formula of
hydrochloric acid
nitric acid
sulfuric acid

Answer 21

hydrochloric acid - HCI
nitric acid - HNO₃
sulfuric acid - H₂SO₄

Question 22

explain the crystallisation method

Answer 22

add excess metal/ insoluble oxide until no more effervescence is observed. reaction is complete
filter the mixture to remove excess insoluble oxide etc
heat the filtrate till saturated
let it cool for pure crystals to form
wash with a little cold distilled water
dry between filter papers

Question 23

in crystallisation method, why do we add excess insoluble oxide

Answer 23

to use up all the acid

Question 24

what is the test and the result of hydrogen

Answer 24

test: place a lighted splint into the mouth of the test tube
result: lighted split extinguishes with a pop sound

Question 25

what is the test and the result of carbon dioxide

Answer 25

test: bubble gas into lime water result: formed white ppt in lime water

Question 26

what is the test and the result of ammonia

Answer 26

test: place moist red litmus paper at the mouth of test tube result: turns moist ed litmus paper to blue

Question 27

what is the test and the result of oxygen

Answer 27

test: place glowing splint in the path of gas result: relights glowing splint

Question 28

what is the test and the result of sulfur dioxide

Answer 28

test: place 1 piece of filter paper soaked with acidified potassium magonate (VII) result: from purple to colourless

Question 29

what is the test and the result of chlorine

Answer 29

test: place moist blue litmus paper in gas result: turns moist blue litmus paper into red and further bleaches it

Question 30

explain the precipitation method

Answer 30

add two aqueous reagents together and stir until no more precipitate is formed filter mixture to obtain the residue wash the residue with a little distilled water to remove impurities dry the precipitate between filter papers

Question 31

explain the titration method

Answer 31

pipette 25.0 cm cube of soluble salt (eg sodium nitrate) and add two drops of indicator = solution turns yellow fill a burette with nitric acid. while swirling the flask, add acid into the solution = turn orange permanently. record the volume of acid needed to cause the colour change!!!! repeat the titration and add the same vol. of dilute nitric acid but without adding the indicator then heat the filtrate until saturated allow saturated solutions to cool so that crystals can form filter to collect crystals as residue wash with a little cold distilled water dry between filter papers

Question 32

salts always contain...

Answer 32

cations and anions