Edexcel Chemistry Unit 3

Front 1

COLOUR OF COPPER (II) CRYSTALS:

Back 1

blue

Front 2

COLOUR OF IRON II CRYSTALS:

Back 2

pale green

Front 3

COLOUR OF CHROMIUM III CRYSTALS:

Back 3

GREEN!

Front 4

COLOUR OF NICKEL II CRYSTALS:

Back 4

GREEN.

Front 5

COLOUR OF MANGANATE II CRYSTALS/SOLUTION:

Back 5

PURPLE!

Front 6

COLOUR OF IRON III CRYSTALS:

Back 6

BROWN!

(looks like dirt really...)

Front 7

COLOUR OF MANGANESE (II) CRYSTALS:

Back 7

pink

Front 8

COLOUR OF CHROMATE (VI) CRYSTALS:

Back 8

YELLOW!!

Front 9

COLOUR OF DICHROMATE (VI)

Back 9

ORANGE.

Front 10

COLOUR OF ZINC (II)

Back 10

COLOURLESS

(how boring)

Front 11

COLOUR OF SODIUM FLAME:

Back 11

YELLOW

Front 12

COLOUR OF POTASSIUM FLAME:

Back 12

LILAC

Front 13

COLOUR OF CALCIUM FLAME:

Back 13

Yellow-RED (like bricks)

Front 14

COLOUR OF LITHIUM FLAME:

Back 14

RED

Front 15

COLOUR OF STRONTIUM FLAME:

Back 15

CRIMSON RED

Front 16

COLOUR OF BARIUM FLAME:

Back 16

PALE GREEN

Front 17

TEST FOR OXYGEN:

Back 17

RELIGHTS SPLINT

Front 18

TEST FOR CO2:

Back 18

TURNS LIMEWATER CLOUDY

Front 19

TEST FOR AMMONIA

Back 19

Turns red moist litmus paper blue

Front 20

TEST FOR NITROGEN DIOXIDE

Back 20

BROWN GAS

(insoluble)

Front 21

TEST FOR HYDROGEN:

Back 21

IGNITES WITH POP

Front 22

TEST FOR HYDROGEN CHLORIDE GAS:

Back 22

steamy fumes when exposed to moist air

Front 23

TEST FOR CHLORINE

Back 23

PALE GREEN GAS

Front 24

TEST FOR BROMINE

Back 24

BROWN GAS

(soluble in organic solvents)

Front 25

TEST FOR IODINE GAS

Back 25

PURPLE GAS

Front 26

TEST FOR WATER VAPOUR:

Back 26

TURNS BLUE COBALT CHLORIDE PAPER PINK.

Front 27

Source of:

Carbon Dioxide emitted with acid

Back 27

Carbonates

Front 28

Source of:

Hydrogen evolved with acid

Back 28

Metals

Front 29

In acids, yellow solution turning orange

Back 29

Chromate (VI) to Dichromate (VI)

Front 30

in acids: Sulfur dioxide evolved and pale yellow precipitate formed

Back 30

thiosulfate

Front 31

How do you test for a reducing agent?

Back 31

1) it decolourises potassium manganate (VII)

2) turns acidified dichromate (VI) from orange to green

Front 32

Name 3 very effective reducing agents:

Back 32

1)iron(II) ions
2)iodide ions

3)hydrogen peroxide.

Front 33

How to test for oxidizing agents:

Back 33

1)it liberates iodine as a brown solution or black solid in aqueous potassium iodide

2)Iodine gives blue/black colour with starch.

Front 34

Give 6 examples of excellent oxidizing agents:

Back 34

1)acidified manganate(VII) ions

2)acidified dichromate(VI) ions

3)hydrogen peroxide

4)copper(II)ions

5)aqueous chlorine

6)aqueous bromine.

Front 35

Manganate (VII) and hydrogen peroxide (H202)?

Back 35

Brown Precipitate

Front 36

Chromium iii + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 36

green precipitate.

soluble

Front 37

manganese ii + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 37

offwhite precipitate

insoluble

Front 38

iron ii + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 38

green precipitate which turns brown

insoluble

Front 39

iron iii+ NH3 gives what colour precipitate and is it soluble or insoluble?

Back 39

brown precipitate

insoluble

Front 40

nickel ii + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 40

green precipitate

soluble ---> forms blue solution

Front 41

copper ii + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 41

blue precipitate

soluble ----> blue solution

Front 42

zinc ii+ NH3 gives what colour precipitate and is it soluble or insoluble?

Back 42

white precipitate

soluble ----> colourless solution

Front 43

magnesium + NH3 gives what colour precipitate and is it soluble or insoluble?

Back 43

white precipitate

insoluble

Front 44

What occurs when SO4 (sulfate) is added to BaCl (and HCl to remove traces)?

Back 44

forms white insoluble precipitate

Front 45

What occurs when SO3 (sulfite) is added to BaCl (and HCl to remove traces)?

Back 45

forms white soluble precipitate

Front 46

What occurs when BaCO2 is added to BaCL (and HCl to remove traces)?

Back 46

precipitate dissolves with effervescence

Front 47

What could you use to test for Sulfate ions (SO4-)?

Back 47

BaCl solution (white precipitate formed)

Front 48

What would you use to test for Halide ions?

Back 48

Use aqueous silver nitrate.

after adding nitric acid to remove any other impurities!

Front 49

What colour is the chloride anion once tested for halide ions after being added to aqueous silver nitrate? Is it soluble?

Back 49

white. Yes, it is soluble

Front 50

What colour is the Bromide anion once tested for halide ions after being added to aqueous silver nitrate? is it soluble?

Back 50

cream. Yes, soluble in excess

Front 51

What colour is the Iodide anion once tested for halide ions after being added to aqueous silver nitrate? is it soluble?

Back 51

yellow. No, insoluble

Front 52

Using sulfuric acid to test for anions in Chloride, what should we see?

Back 52

steamy fumes, vigorous reaction

Front 53

Using sulfuric acid to test for anions in Bromide, what should we see?

Back 53

steamy fumes, brown vapour, vigorous reaction

Front 54

Using sulfuric acid to test for anions in Iodide, what should we see?

Back 54

steamy fumes, black solid, purple vapour, yellow solid, vigorous reaction

Front 55

If an organic compound dissolves in water what is it likely to be?

Back 55

- Amines

-carboxylic acids

-phenols

Front 56

How would you test for alkenes?

Back 56

shake with orange bromine water, yellow solution is decolourised.

Front 57

How would you test for primary/secondary alcohols, aldehydes?

Back 57

warm with acidified potassium dichromate(VI)

turns orange-----> green

Front 58

How would you test for phenols?

Back 58

shake with orange bromine water.

white precipitate is formed.

Front 59

How would you test for halogenoalkanes with Cl, Br and I anions?

Back 59

warm with aqueous sodium/potassium hydroxide, acidify with dilute nitric acid then add aqueous silver nitrate

precipitates: Cl- white

Br- cream

I- yellow

Front 60

How would you test for the OH group in alcohols and carboxylic acids?

Back 60

phosphorus(V) chloride

steamy fumes of HCl that turn damp blue litmus paper red

Front 61

How to test for C=O groups in aldehydes and ketones?

Back 61

use

2,4−dinitrophenylhydrazine solution

-orange precipitate

Front 62

More tests for aldehydes?

Back 62

-boil with Benedict's solution ---> blue to red!

-warm with Tollen's agent ---> forms silver mirror!

Front 63

How to test for carboxylic acids?

Back 63

add sodium or potassium carbonate or hydrogencarbonate solution ----> effervescence

Front 64

Test for alcohols?

Back 64

warm with carboxylic acid and a few drops of concentrated sulfuric acid

-----> gives ester-smell like glue

Front 65

Test for aromatic amine?

Back 65

sodium nitrite and dilute hydrochloric acid followed by an alkaline solution of phenol in ice-cold conditions -----> orange precipitate.

Front 66

Test for methyl ketone or athanal?

Back 66

iodine in alkaline solution ----> pale yellow precipitate.

Front 67

Simple way for testing for alcohol, phenol or carboxylic acid

Back 67

add a small piece of sodium ----> effervescence.

Front 68

How do you carry out a flame test?

Back 68

1) first, the chromium of platinum wire is dipped in to HCL so it becomes a chloride salt. Chloride salts are the most volatile so they turn into gas as soon as they enter the flame.

2) make sure the flame is colorless.

3) observe colour.

Front 69

Why do flames turn different colors when they detect a specific cation?

Back 69

the heat energy of the flame causes the compound to vaporize so that an electron in the metal jumps up to a higher energy level. When the electron falls back down an energy level, energy is released in the form of light in different wavelengths which are different colors.

Front 70

Source of Carbon Dioxide from solids:

Back 70

metal carbonates

Front 71

Source of Oxygen from solids:

Back 71

group 1 nitrates

Front 72

source of oxygen + nitrogen dioxide from solids:

Back 72

group 2 nitrates

Front 73

source of water from solids:

Back 73

hydrated solids or hydrogen carbonate

Front 74

A white solid sublimes on the cooler part of the tube ?

Back 74

ammonium salt is present

Front 75

How to test for sulfur dioxide:

Back 75

it is a colorless gas which is acidic and decolourises acidified potassium dichromate paper/solution from green to orange.

Front 76

Source of sulfur dioxide?

Back 76

-warming an acid with sulfite.

-burning sulfur

-reducing concentrated sulfuric acid.

Front 77

Test for nitrogen dioxide:

Back 77

brown gas

Front 78

Test for chlorine with litmus paper?

Back 78

turns moist red litmus paper blue then bleaches it white.

Front 79

Test for Bromine:

Back 79

pass through a solution of excess potassium iodide and the colorless solution becomes deep red brown because the iodide is liberated and then reacts with excess I- ions. Excess iodide would give a grey black precipitate thats black.

Front 80

Effervescence of a colorless, odorless gas which gives a white precipitate with limewater.

Back 80

carbonate or hydrogen carbonate

Front 81

sulfur dioxide evolved on warming and decolourises acidified potassium dichromate (vi) paper to green (from orange)

Back 81

sulfite

Front 82

Test for reducing agents:

Back 82

decolourises aqueous acidified potassium manganate (vii) form purple to colourless OR turns acidified potassium manganate from orange to green.

Front 83

What are some really good reducing agents?

Back 83

- iron (ii) ions

- iodide ions

-hydrogen peroxide

-sulphite ions

Front 84

Add hydrogen peroxide, and get a brown precipitate?

Back 84

MNO2

Front 85

Add hydrogen peroxide, and purple solution decolourises

Back 85

mangante (vii) in acid

Front 86

Add hydrogen peroxide and pale green solution turns yellow

Back 86

iron ii to iron iii in acid.

Front 87

What are the soluble ionic compounds?

Back 87

- group 1 salts

-ammonium salts

-all nitrates

-all chlorides except silver and lead

- all sulfates except barium, strontium, lead.

Front 88

Which are insoluble compounds?

Back 88

all carbonates apart from group 1 carbonates and ammonium carbonates.

all hydroxides apart from group1 hydroxides, barium hydroxide and ammonium hydroxide.

Front 89

Test for group 1 hydrogencarbonates:

Back 89

-drops of water condense on upper part of tube when heated.

-Gas produced also makes limewater milky.

Front 90

Test for sodium/ potassium nitrates:

Back 90

Under heat:

-melts and gives off bubbles of a colorless gas which relights a glowing splint

Front 91

Test for lithium or a group 2 nitrate under heat:

Back 91

Under heat:

-melts and gives off brown gas and a gas that is colorless and relights splint.

Front 92

Test for group 2 carbonates or lithium carbonate under heat:

Back 92

Under heat:

-no water produced like hydrogen carbonates but gas evolved turns lime water milky

Front 93

Test for ammonium chloride under heat:

Back 93

-solid sublimes in upper part of test tube

Front 94

What are the products formed in a thermal decomposition of a group 1 nitrate?

Back 94

- a NO2 (a nitrogen dioxide)

-O2 (oxygen)

e.g: 2KNO3 ------> 2KNO2 + O2

Front 95

What are the products formed in a thermal decomposition of a group 2 nitrate?

Back 95

-an oxide

-a nitrogen dioxide

-Oxygen

e.g: 2Mg(NO3)2 ------> 2MgO + 4NO2 + O2

Front 96

Test for carbonates, hydrogen carbonates with acid:

Back 96

-effervescence (bubbles)

-limewater goes milky

Front 97

How do you distinguish a carbonate from a hydrogen carbonate?

Back 97

If it is a hydrogen carbonate:

test with boiling water and there should be effervescence and gas evolved that turns limewater milky.

OR

-make a solution with the unknown carbonate and add calcium chloride solution. There should be a white precipitate IF there is a carbonate and no precipitate if it is a hydrogen carbonate.

Front 98

How to test for ammonium salts not under heat:

Back 98

-add to sodium hydroxide and test gas with either damp litmus paper.

OR a glass rod dipped into concentrated HCL.

Results:

-gas turns red litmus paper blue and blue litmus paper stays blue (ammonia formed)

-white smoke (ammonium chloride)

Front 99

Test for inorganic chloride:

Back 99

-add concentrated sulfuric acid and test gas formed with 1) glass rod dipped in ammonia or 2) damp litmus paper.

results:

1)bubbles, steamy fumes (hydrogenchloride)

2)white smoke, red litmus paper stays red blue turns red.

test this in a fume cupboard

Front 100

Test for inorganic Bromide:

Back 100

Add sulfuric acid

results:

steamy fumes (hydrogen bromide), red-brown gas (bromine)

Front 101

Test for inorganic Iodide:

Back 101

Add sulfuric acid

results:

steamy fumes (hydrogen iodide), purple vapour (iodine), yellow solid (sulfur), bad smelling egg-smell (H2S)

Front 102

More tests for the chloride, bromide and iodide halides:

Back 102

-Add dilute nitric acid to the solution of the unknown and then silver nitrate.

finally, test solubility of precipitate with first dilute, then concentrated ammonia

results:

-chloride (white precipitate turning purple) soluble in dilute ammonia

-Bromide (cream precipitate) insoluble in dilute but soluble in concentrated ammonia

-Iodide (yellow precipitate) insoluble in concentrated ammonia

Front 103

What is the ionic equation for the precipitation of a silver halide?

Back 103

Ag+ (aq) + X- (aq) -----> AgX (s)

'X' is the halide

Front 104

How to test for the bromide or iodide halides without using alkali:

Back 104

using chlorine water and then add starch solution

results:

-brown or yellow solution formed (bromine or iodine formed)

- test with starch should turn blue-black IF it is an Iodide but not bromide.

Front 105

Test for sulfates:

Back 105

add HCL then barium chloride

-white precipitate formed

Front 106

Test for nitrates without heating:

Back 106

-Add Devarda's alloy (aluminum powder)

and dilute sodium hydroxide and warm with dilute sodium hydroxide then test the gas using a rod dipped into HCL (white smoke) or litmus paper turns blue.

Front 107

How to test for hydroxides and which hydroxides are soluble and which are not?

Back 107

Add sodium hydroxide:

calcium ----> slight white precipitate

magnesium --->white precipitate

soluble:

-group 1 hydroxides

-calcium hydroxide slightly soluble

insoluble:

-magnesium hydroxides.

Front 108

How to test for an acid:

Back 108

-add zinc or magnesium and test the gas that is evolved.

there should be effervescence and gas ignites with squeaky pop.

Front 109

Sherlock's corner:

"it burns with a clean, non smoky flame"

when heated (what sort of hydrocarbon is it)?

Back 109

low carbon to hydrogen ratio so could be an alcohol

Front 110

Sherlock's corner:

"it burns with a smoky flame"

when heated

Back 110

high carbon to hydrogen ratio so could be cyclic alkene or alkane

Front 111

Testing for hydrocarbons?

Back 111

-add to water. Two layers form so it is a hydrocarbon

-dissolves then it is an alcohol ( it hydrogen bonds with water)

Front 112

Testing for the c=c bond to find if something is an alkene?

Back 112

-Add orange bromine water and shake:

the orange bromine water decolourises and two layers form.

-Add sulfuric acid then potassium manganate (vii) and shake. ---> purple solution becomes colorless and two layers form

Front 113

Test for the OH group:

Back 113

-add a small piece of sodium and there should be effervescence, sodium disappears or a white solid forms.

or

-add phosphorus (v) chloride and test for gas using rod dipped in ammonia ---> steamy fumes, white smoke

Front 114

What experiment would we use to differentiate between a primary, secondary and tertiary alcohol?

Back 114

Add sulfuric acid and aqueous potassium dichromate (vi) then warms in beaker with hot water.

Orange solution turns green (primary or sec)

solution stays orange (tertiary)

Front 115

Whats one way we can test for a halogenoalkane using ethanol?

Back 115

add concentrated sodium hydroxide in ethanol and fit the test tube with a delivery tube and warm gently passing any gas evolved in orange bromine water which should become colorless in the presence of one.

Front 116

Sherlock's corner:

this halogenoalkane precipitate completely dissolves in ammonia

Back 116

it is a chloroalkane!

Front 117

Sherlock's corner:this halogenoalkane precipitate only dissolves in concentrated ammonia

Back 117

is is a bromoalkane

Front 118

Sherlock's corner:this halogenoalkane precipitate does not dissolve in ammonia

Back 118

is is an iodoalkane

Front 119

Are halogenoalkanes soluble in water?

Back 119

NO! two layers form.

Front 120

How does the OH bond appear on the IR spectra?

Back 120

its looks very broad

Front 121

What is the absorption frequency of the C-H bond?

Back 121

3000-3853

Front 122

What is the absorption frequency of the c=c bond?

Back 122

1669-1645

Front 123

What is the absorption frequency of the OH bond?

Back 123

a broad beak at 3750-3200

Front 124

When carrying out a titration experiment, how can we avoid any errors?

Back 124

-weighing: weigh to 0.01g

-measure all titre volumes to 0.05 cm3

-pipette: wash out with solution before use and ensure that their are no bubbles in the stem of the pipette when used.

-burette:washed with solution and filled just above 0 mark.

-recording: read at the bottom of the meniscus

-consistency: repeat titrations so that we get at least two that are concordant which can be added and divided by two to get the average titre.

Front 125

What is a titre?

Back 125

the difference between the first and initial readings in a titration

Front 126

Describe how iodine/thiosulfate titrations are carried out:

Back 126

-weigh solid oxidising agent and dissolve in water to make 250cm3 (or use aqueous hydrogen peroxide as the oxidizing agent). 25cm3 portions of the oxidizing agent solution are pipetted into a conical flask and some sulfuric acid is added. Excess potassium iodide is also added which reacts with the oxidizing agent to liberate iodine which is then titrated against a solution of sodium thiosulfate until it fades to a pale yellow colour. Starch is then added drop by drop until the blue black colour disappears (no more starch).

Front 127

What is the formula for heat change in enthalpy change experiments?

Back 127

mass of solution x specific heat capacity (4.18 for water) x enthalpy change

Front 128

How would you conduct an enthalpy change experiment?

Back 128

1)mix measured amounts and stir with thermometer in the polystyrene cup in the glass cup then measure the initial and final temp (for rapid reactions like acid/base or acid/carbonate.

2)record the initial temp of one solution then begin adding the other solution at regular intervals measuring the temp and plotting a graph of temp against volume

Front 129

What are some technical errors that could occur during an enthalpy change experiment?

Back 129

-not using the bottom of the meniscus to read to volumes.

-failing to stir the mixture thoroughly so not observing correct temperature.

-not adding the solid (such as a carbonate) in small portions carefully so when gas is produced, liquid spills out and foams.

Front 130

What are some recording errors that could occur during an enthalpy change experiment?

Back 130

-failing to record masses to 0.01g

-failing to record the temperature to 0.1 (always on decimal place)

-failing to record time correctly per minute

Front 131

How would you measure the percentage error of a thermometer?

Back 131

error for each reading is + or - 0.1 for a thermometer so we would use this formula:

0.1

_________ x 100%

ΔT

Front 132

Would increasing the volume of a solution increase/decrease the percentage error of a thermometer? Why?

Back 132

increasing the volume of the liquid will increase the heat, but so would the mass so it is proportional and the ΔT won't be affected. BUT if you increase the concentration then the ΔT will be affected meanwhile the mass won't change so more heat would be produced making it more accurate.

Front 133

How do we prepare a simple salt?

Back 133

1)the solid reactant is added to the acid which has been gently heated

2) the mixed solution is now filtered through a funnel and poured into an evaporating basin (dish) and heated until only half of the filtrate remains

3) leave overnight to cool and form crystals and blot dry with filter paper and weigh

Front 134

What technical errors could we face when conducting an experiment to prepare a simple salt?

Back 134

-acid solution is not hot enough (to dissolve solid).

-adding solid too fast that the solid causes the liquid to froth and overflow

-evaporating too little/too much of the solution.

Front 135

When forming a salt, later onwards, how would we measure the crystals?

Back 135

- measure to 2 decimal places

-describe salt's colour and shape (diamond)

Front 136

How would you prepare the double-salt Ammonium Iron (ii) sulfate?

Back 136

1)some iron fillings are placed with an excess of hot sulphuric acid meanwhile any unreacted iron is filtered off.

2)Dilute ammonia is added in portions to another beaker with dilute sulfuric acid until the solution becomes alkaline and turns litmus paper blue. The excess ammonia is boiled off.

3) the two solutions are mixed together in a beaker and heated until half the volume and is then left to cool

Front 137

How will you prepare the experiment for the oxidation of a primary alcohol to form an aldehyde?

Back 137

1) an alcohol is dissolved in a solution of potassium dichromate (vi) slowly and sulfuric acid which is then connected to the distillation apparatus and heated using the bunsen burner.

2) when it cools down from the water passing through the condenser, it cools down and enters a separate beaker as an aldehyde.

Front 138

What is the equation for the oxidation of ethanol:

Back 138

CH3CH2OH + (O) ---------> CH3CHO + H20

Front 139

How will you prepare the experiment for the oxidation of a primary alcohol to form a carboxylic acid?

Back 139

use same procedure to form primary alcohol but do not use distillation apparatus but heat under reflux until solution becomes green (from orange) due to the presence of the chromium iii ions from the acidified dichromate and becomes a ketone from the aldehyde.

Front 140

How do you distinguish between aldehydes and ketones?

Back 140

add 2,4 dinitrophenylhydrazine to produce and orange precipitate.

-then add tollens reagent:

should form a silver mirror in the presence of an aldehyde but no change in the presence of a ketone.

or add Benedict's solution:

gives red precipitate from blue in the presence of an aldehyde but stays blue with ketones.

Front 141

How do you dehydrate an alcohol? Use an example.

Back 141

add an alcohol such as cyclohexanol to concentrated phosphoric acid which becomes a cyclohexene that is distilled. This can be tested using orange bromine water which decolourises.