C8 - Chemical Analysis

Question 1

What is the set up for a flame test

Answer 1

Platinum or nichrome wire cleaned with concentrated hydrochloric acid - then wire dipped into a sample of the compound - the placed in blue Bunsen flame

Question 2

Type of metal for the wire for a flame test

Answer 2

Platinum

Question 3

What type of flame is wire put into for flame tests

Answer 3

Blue Bunsen flame

Question 4

What colour does lithium go and why

Answer 4

Lithium crimson - both have an I in them

Question 5

What colour does sodium go and why

Answer 5

Yellow - soooo yellow

Question 6

What colour does copper go flame test

Answer 6

Green - as 2 ps in copper and 2 es in green

Question 7

What colour does potassium go?

Answer 7

Lilac - the fourth letter of both is A

Question 8

What colour does calcium go in flame test?

Answer 8

orange Red
Calcium = Rad = Red

Question 9

Give 2 possible issues with the flame test

Answer 9

If wire not clean/mixture of metal ions present
Yellow Bunsen burner flame could mask the colour of the flame produced

Question 10

What is the result of the sodium hydroxide precipitate test for aluminium, calcium and magnesium (colour)

Answer 10

White

Question 11

Which compound dissolved as well as turning white in the sodium hydroxide precipitate test?

Answer 11

Aluminium

Question 12

What colour does copper 2 turn in the sodium hydroxide precipitate test

Answer 12

Blue (as they rhyme)

Question 13

What colour does iron 2 turn in the sodium hydroxide precipitate test?

Answer 13

Green - as II => ee

Question 14

What colour does iron 3 turn in sodium hydroxide precipitate test

Answer 14

Brown
Iron has o n and brown has own

Question 15

What 3 compounds are usually used with the sodium hydroxide test? And why?

Answer 15

Copper, iron II, iron III as it has differentiating colours

Question 16

How do you test the difference between aluminium, calcium or magnesium

Answer 16

Add excess sodium hydroxide solution
Aluminium precipitate dissolves forming a colourless solution

Question 17

What is necessary to add for a carbonate test?

Answer 17

Hydrochloric acid

Question 18

How do you conduct the carbonate test

Answer 18

Collect bubbles with a pipette and bubble this into limewater - check if limewater turns cloudy

Question 19

What is necessary for the sulfate test to be conducted

Answer 19

Add dilute HCl and Barium chloride solution

Question 20

What forms if sulfate ions are present?

Answer 20

White precipitate

Question 21

What is necessary for the halide test?

Answer 21

Nitric acid and silver nitrate solution

Question 22

Give 3 types of precipitate possible for the halide test

Answer 22

White
Cream
Yellow

Question 23

What is the positive result for chloride in a halide test

Answer 23

Forms white precipitate - as chloride is clean white

Question 24

What colour does bromide go in a halide ion test

Answer 24

Cream - as A B C

Question 25

What is the positive colour for iodide

Answer 25

Yellow - I love Yellow

Question 26

What is an accurate way to test for ions

Answer 26

Flame emission spectroscopy

Question 27

Give 4 advantages of flame emission spectroscopy

Answer 27

Can identify ions in a mixture More sensitive More accurate More rapid

Question 28

How does flame emission spectroscopy work?

Answer 28

Sample is put in flame Light emitted is passed through a spectroscope and a line spectrum emerges

Question 29

How are ions identified in flame emission spectroscopy?

Answer 29

A line spectrum unique to each ion type exists You can compare this to the result you get to identify ion presence

Question 30

Give 2 ways flame emission spectroscopy can be used

Answer 30

Checks for presence of ions Measures concentrations of ions in a substance

Question 31

5what is a formulation

Answer 31

Mixture designed to produce a useful product

Question 32

How do you find an impure substance

Answer 32

The melting points is lower and the boiling point is higher than the pure substance’s value

Question 33

What is the gas test for oxygen

Answer 33

Glowing splint into gas - if it relights oxygen is present

Question 34

What is gas test for hydrogen

Answer 34

Squeaky pop test - burning splint in gas and if it leads to squeaky pop then hydrogen present - as hydrogen burns rapidly

Question 35

What is the gas test for CO2

Answer 35

Bubble the gas into limewater - and goes from colourless to cloudy if positive

Question 36

What is the test for chlorine

Answer 36

Damp blue litmus paper placed in the gas - positive is the paper bleaches (blue->red->white)

Question 37

what is a pure substance

Answer 37

a single element or compound - not mixed with anything else

Question 38

what can be used to distinguish between pure things and mixtures

Answer 38

melting and boiling point data

Question 39

in everyday language what does pure mean

Answer 39

a substance with nothing added - like pure milk

Question 40

what is a formulation

Answer 40

a mixture designed as a useful product

Question 41

how are formulations made

Answer 41

components mixed in carefully measured quantities to ensure the product has the required properties

Question 42

give 5 examples of formulations

Answer 42

fuels cleaning agent s paints medicines alloys fertilisers food

Question 43

what is chromatography for (2)

Answer 43

separate mixtures help identify substances

Question 44

what are the two phases in chromatography

Answer 44

stationary and mobile

Question 45

what does separation depend on

Answer 45

the distribution of substances between stationary and mobile phases

Question 46

what is the Rf value

Answer 46

distance moved by compound to distance moved by solvent

Question 47

what is the distance moved by the compound as a distance

Answer 47

centre of spot from origin

Question 48

different compounds have different R f values in different ___

Answer 48

solvents

Question 49

a pure compound will produce ___spot in all solvents

Answer 49

a single

Question 50

give a precaution of the chromatography practical

Answer 50

don't get food colouring in eyes

Question 51

what is limewater

Answer 51

calcium hydroxide

Question 52

when CO2 is __or __through limewater it turns ___

Answer 52

bubbled through shaken with cloudy

Question 53

what is the test for chlorine

Answer 53

damp litmus paper put into chlorine gas until bleached and turns white

Question 54

what happens if the sample contains a mixture of ions in a flame test

Answer 54

the colours of the flames can be masked

Question 55

what metal ions can flame tests identify

Answer 55

cations

Question 56

what types of metal ions can sodium hydroxide be used to identify

Answer 56

cations

Question 57

only ___precipitate dissolves in excess sodium hydroxide solution

Answer 57

aluminium hydroxide

Question 58

what 3 ions form white precipitates when sodium hydroxide is added

Answer 58

aluminium calcium magnesium

Question 59

what colour precipitates do copper II, ironII and iron III form in sodium hydorxide solution

Answer 59

blue green brown respectively

Question 60

carbonate react with what to form carbon dioxide gas

Answer 60

dilute acids

Question 61

how do halide ions produce precipitates - in what reaction

Answer 61

silver nitrate and dilute nitric acid

Question 62

what colour is silver chloride

Answer 62

white

Question 63

what colour is silver bromide

Answer 63

cream

Question 64

what colour is silver iodide

Answer 64

yellow

Question 65

sulfate ions produce a white precipitate when reacted with what

Answer 65

barium chloride dilute hydrochloric acid

Question 66

instrumental methdos are __ ___and __

Answer 66

accurate sensitive rapid

Question 67

give an example of an instrumental method to analyse metal ions

Answer 67

flame emission spectroscopy

Question 68

how does flame emission spectroscopy work

Answer 68

sample in flame ,light passed through a spectroscope output is a line spectrum to identify metal ions and measure concentrations