Further Analysis Flashcards

1
Q

Pure substance

A

A single element or compound not mixed with any substance

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2
Q

Formulation

A

A mixture of substances designed to be a useful product

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3
Q

Impure substance

A

A substance that contains other substances (impurities)

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4
Q

How to identify pure vs impure substance

A

A pure substance has a fixed melting and boiling point. An impure substance has a range of temperatures.

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5
Q

Hydrogen gas test

A

Lit splint in test tube → gas burns with squeaky pop

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6
Q

CO2 test

A

Bubble gas through limewater → White prep

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7
Q

Cl test

A

Damp blue litmus paper → Bleaches

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8
Q

Alkene

A

Bromine water → Orange to colourless

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9
Q

Acid/Alkali

A

Indicators colour change

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10
Q

pH

A

Universal indicator → colour change

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11
Q

Acid

A

Add metal carbonate

Bubble gas through limewater

If CO2 produced goes cloudy

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12
Q

Excited electrons

A
  • When provided with energy, electrons are promoted to higher energy levels in the atom, e.g. thermal energy
  • They then drop down to ground state, releasing energy.
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13
Q

Why do excited electrons produce light

A
  • Different atoms have different electron arrangements, giving off different light frequencies.
  • Some frequencies are in the visible region of the EM spectrum.
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14
Q

Li+ (flame)

A

Crimson

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15
Q

Na+ (flame)

A

Yellow

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16
Q

K+ (flame)

A

Lilac

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17
Q

Ca 2+ (flame)

A

Orange/Red

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18
Q

Cu 2+ (flame)

A

Green

19
Q

Limitations of flame tests for identifying ions

A
  • Some colours of flame are hard to tell from their background
  • Some metals give similar colours of flame
  • Some metals give no flame colour as the frequency they give off is not in visible light e.g. UV rays or Infrared

A mixture of metals will give a mixture of colours. One colour may mask the others.

20
Q

Al 3+ NaOH

A

White

21
Q

Ca 2+ NaOH

A

White

22
Q

Mg 2+ NaOH

A

White

23
Q

Cu 2+ NaOH

A

Blue

24
Q

Fe 2+ NaOH

A

Green

25
Q

Fe 3+ NaOH

A

Brown

26
Q

Stationary phase

A

Paper

27
Q

Mobile phase

A

Water

28
Q

Separates chemicals based on the

A

Solubility of components.
The more soluble it is, the more it moves across the chromatogram in a given time.

29
Q

Rf values from chromatographs

A

Distance chemical moves /
Distance solvent moves

30
Q

Rf values to draw conclusions about substances

A
  • Pure substances will show one result per chemical.
  • Mixtures will show more than one.
  • Identical chemicals will move at the same rate. → The retention factor (proportion of the chromatograph they cover) will be the same.
31
Q

Carbonate ions

A

Add a dilute acid → Effervescence

MUST BE DONE FIRST. CARBONATES GIVE FALSE POSITIVE RESULTS.

32
Q

Sulfate ions

A

Add HCl to check for no CO

Add BaCl → White precipitate

33
Q

Halide ions

A

Add HNO3 to check for no CO

Silver nitrate

(dissolves in dilute NH4OH)

34
Q

Cl-
Br-
I-

A

White
Cream
Yellow

35
Q

Flame emission spectroscopy description

A

Mechanical methods to scan individual frequencies of light

36
Q

Advantages of flame spectrometry

A

Even tiny quantities of metal can be identified

Mixtures can be analysed and compared to known spectra to identify the contents

37
Q

Uses

A

Detection of trace elements

Determining the composition of stars

38
Q

Qualitative chemical tests

A

Simple

Inaccurate
Requires larger samples

39
Q

Instrumental tests

A

Rapid
Sensitive
Accurate

Expensive

40
Q
  • Describe why qualitative may be used over instrumental
A

Simpler and less expensive

41
Q
A
42
Q

Mass spectrometer

A

Reports relative mass of compounds

43
Q
A

Separates mixture by compounds so that they can be identified and gives their concentration