Acids And Analytical Chemistry

Front 1

What colour does litmus paper turn?

Back 1

Acid - red

Alkali - blue

Front 2

What colour does phenolphthalein turn?

Back 2

Acid - colourless

Alkali - pink

Front 3

What colour does methyl orange turn?

Back 3

Acid - red

Alkali - yellow

Front 4

On the pH scale, what does each number mean?

Back 4

7 - neutral

1 - strong acid

6 - weak acid

8 - weak alkali

14 - strong alkali

Front 5

Define an acid

Back 5

Acids are substances which dissociate in water and release hydrogen ions (h+)

Front 6

Define an alkali

Back 6

Alkalis are substances which dissolve in water to release hyrdoxide ions (OH-)

Front 7

What is the name for a reaction between an acid and alkali?

Back 7

Neutralization?

Front 8

Equation for neutralization?

Back 8

H+ (aq) + OH- (aq) --> H20 (l)

Front 9

What are the products of a metal and acid reaction?

Back 9

Salt + hydrogen

Front 10

What are the products of a metal oxide and acid reaction?

Back 10

Salt + water

Front 11

What are the products of a metal hydroxide and acid reaction?

Back 11

Salt + water

Front 12

What are the products of a metal carbonate and acid reaction?

Back 12

Salt + water + carbon dioxide

Front 13

What is hydrogen chloride?

Back 13

A halogen compound -- covalent compound which has a low melting and boiling point and does not conduct electricity.

Front 14

What does hydrogen chloride do in water?

Back 14

When dissolved in water it dissociates to become hydrochloric acid.

Front 15

What are the features of hydrochloric acid?

Back 15

Corrisive

Low pH

Reacts easily with metals, bases and metal carbonates

Front 16

Equation for dissociation of hydrogen chloride?

Back 16

HCl (g) + H2O (l) --> H3O+ (aq) + Cl- (aq)

Front 17

Simplified equation for dissociation of hydrogen chloride?

Back 17

HCl (aq) --> H+ (aq) + Cl- (aq)

Front 18

What happens when hydrogen chloride is added to methylbenzene?

Back 18

The dissociation process does not occur and as a result hydrogen chloride does not behave like an acid (does not change colour of universal indication and does not conduct electricity)

Front 19

Which salts are soluble?

Back 19

All nitrates

All chlorides except silver and lead

All sulphates except barium, lead and calcium

Sodium and potassium carbonates

All sodium, potassium and ammonium salts.

Front 20

Which salts are insoluble?

Back 20

Silver chloride and lead chloride

Barium, lead and calcium sulphate

All carbonates except sodium and potassium

Front 21

How do we make samples of pure dry crystals of a salt if the salt is not soluble?

Back 21

Precipitation or the process of obtaining dry salt from solution

Front 22

What is the process of Precipitation?

Back 22

Make 2 solutions each one containing 1 ion of the salt to be madeAdd solutionFilter off precipitate which is the insolube saltWas the residue with distilled water to remove any of the salt solutionsDry with filter paper or on warm gauze

Front 23

What is the process of obtaining dry salt from solution?

Back 23

Concentrate solution until it becomes saturated which is done by driving off most of the water by heating it. Solution is saturated when crystals form on a glass rod dipped in the solution.

Stop heating and allow sollution to cool and salt crystals to form

FIlter the crystals to remove water

Wash crystals with distilled water to remove any remaining acid/alkali

Dry crystals with filter paper or place on warm gauze.

Front 24

How do we make samples of pure dry crystals of a salt if the salt is soluble with a soluble base?

Back 24

Titration:

Add acid via burette to alkali + indicator until neutral (or until temperature stops rising)

Measure volume of acid added : throw away solution as it contains the indicatior

Add same volume of acid to same amount of alkali without inidcator

Obtain dry salt from solution

Front 25

How do we make samples of pure dry crystals of a salt if the salt is soluble with an insoluble base?

Back 25

Add excess base:

Add excess base to acid until no more dissolves (warm if necessary)

Filter off excess base

Obtain salt solution.

Front 26

How to carry out flame test?

Back 26

Nichrome wire in nitric acid and then burnt in flame until colourless. Clean again in acid and then dip into sample that needs to be tested. Sample held in flame with air inlet hole open.

Front 27

Flame test results for:

Li+

Ca2+

K+

Na+

Ba2+

Sr2+

Cu2+

Back 27

Bright red

Brick red

Lilac

Golden yellow

Apple green/yellow

Crimson

Blue/green

Front 28

Test for:

Fe2+

Fe3+

Al3+

Cu2+

Back 28

Add aqueous sodium hydroxide (NaOH)

Green precipitate

Brown precipitate

White precipitate (dissolves in excess)

Blue precipitate

Front 29

Test for NH4 +

Back 29

Add aqueous sodium hydroxide (NaOH) and warm, test gas given off with damp red litmus paper (should turn blue)

Front 30

Tests for:

Cl-

I-

Br-

Back 30

Acidify with dilute nitric acid (HNO3) and add aqueous silver nitrate (AgNO3).

White precipitate

Yellow precipitate

Cream precipitate

Front 31

Test for CO3 2-

Back 31

Add HCl. Fizzing produces CO2 (test by bubbling gas through limewater - it turns cloudy)

Front 32

Test for SO4 2-

Back 32

Acidify with hydrochloric acid (HCl) and add aqueous barium chloride (BaCl2).

White precipitate

Front 33

Test for hydrogen gas

Back 33

Lighted splint -squeaky pop

Front 34

Test for oxygen gas

Back 34

Glowing splint - relights

Front 35

Test for carbon dioxide gas

Back 35

Bubble through limewater - turns cloudy

Front 36

Test for ammonia gas

Back 36

Damp red litmus paper - turns blue

Front 37

Test for chlorine gas

Back 37

Damp red/blue litmus paper - bleaches