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Chem > Ch1 Separation and Collection > Flashcards

Ch1 Separation and Collection Flashcards

CREDITS TO GOOGLE for the stuff idk

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1
Q

1. How issit separated

  1. Fixed what?
  2. Cannot be a…?

Pure Substances Properties

A
  1. Cannot, separated, physical, means
  2. Fixed, boiling, point, fixed, density
  3. Cannot be a mixture
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2
Q

3 total, opposite of pure

Impure Substances Property

A
  1. Can, separate, physical, means
  2. boils/melts over range of temp, no fixed density
  3. Can be a mixture
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3
Q

The higher the Mr, the ____ the gas

A

denser

THINK ABOUT IT
As the relative mass increases, the density also increases

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4
Q

Solid-solid separation methods

A
  • Magnetic separation
  • Sublimation
  • Filtration

decanting is solid liquid btw

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5
Q

Example of sublimeable solids

A
  • Iodine
  • Dry Ice
  • Ammonium Chloride
  • Naphthalene (moth balls)

ALL these are in solid state.

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6
Q

Liquid-solid separation methods

A
  • Filtration
  • Decanting
  • Evaporation to dryness
  • Crystallisation
  • Simple Distillation (Must be DISSOLVED solid w/ liquid aka solution with solvent)

Fractional Distillation usually liquid liquid!!

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7
Q

Liquid-liquid separation methods

A
  • Circular Paper Chromatography
  • Ascending Paper Chromatography
  • Simple Distillation
  • Fractional Distillation
  • Separating Funnel
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8
Q

What is the Mr of air?

A

30

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9
Q

I have solid ammonium chloride and solid calcium chloride. How do I separate both of these?

A

Using sublimation

LINK
3 sublimeable solids
- ammonium chloride (s)
- iodine (s)
- dry ice (s)

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10
Q

I have huge and numerous silver chloride crystals and Solution X in a beaker. How do I separate both of them?

A

Decanting

huge and numerous

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11
Q

I have numerous granules of sand and solid sodium chloride in a beaker. How do I separate them?

A
  1. add water, stir thoroughly until sodium chloride completely dissolve
  2. filter mixture
  3. retrieve, pour filtrate onto evaporating dish, evaporate to dryness
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12
Q

Gas syringe diagram

A

https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit page 5

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13
Q

I have soluble acetate that is heat-stable(aq) and water, how do I separate this mixture?

A

Evaporation to dryness.

(aq) cannot use filtration.

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14
Q

I have soluble, huge and numerous solid Y that is not heat-stable. I want to separate it with Solution X that it is dissolved in. How do I do it?

A

Crystallisation.

soluble but not heat-stable is the key here!

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15
Q

Wat is crystallisation?

A

Heating to, point of saturation

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16
Q

How does crystallisation work?

A

changing, solubility of solid with temperature
- temp increases -> solubility increases
- temp decreases -> solubility decreases, crystals formed

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17
Q

What happens to crystals in crystallisation when you overheat it? Why?

A

decomposes when heated

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18
Q

What is the point of saturation? How to check for saturation point?

A

What it is
Where biggest crystals, formed

How to check
Dip a cold, clean glass rod
Positive: Crystals form, glass rod
Negative: No crystals form, glass rod

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19
Q

For Chromatography, how do we see which solutes are of lowest solubility?

A

nearer to the ink dot = lower solubility

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20
Q

What must take note when making ascending paper chromatography?

A
  • Solvent, below startline
  • Startline drawn, graphite pencil
  • high solvent front
  • cannot let solvent front travel 2 edge of paper
  • lid cover beaker, solvent
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21
Q
  1. Does a solute have different solubility in different solvents?
  2. Why cannot draw startline with pen?
A
  1. Yes
  2. Pen, soluble in water, affect chromatography results, graphite in pencil, insoluble in water
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22
Q

Rf Value Formula

A

Dist travelled by component/Dist between solvent front and starting line

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23
Q

3 Locating Agents + What are locating agents used for?

A
  • Ninhydrin
  • UV light
  • Iodine

Detect, colourless, substances, on chromatogram

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24
Q

3 Uses of simple distillation

A
  • Crude Oil Separation
  • Distillation obtain alcohol, perfumes
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25
Q

How to increase efficiency of separation for FRACTIONAL DISTILLATION

A

longer fractionating column

longer fractionating column = better separation

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26
Q

What is the Water Bath for in Distillation?

A

What is it for?
prevent direct heating, if any flammable gases are in round bottomed flask, will not catch fire.

THINK ABOUT IT

Direct heating + flammable gases is some trouble, it will cause it to catch fire. Thats why its called “flammable” after all

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27
Q

Where is the water bath placed in distillation?

A

Around the round-bottomed flask

That is where the initial flask is (containing all the initial sol.)

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28
Q

Where is the thermometer put in distillation setup? Why?

A

Put at the mouth of the condenser

Why?
accurately measure the boiling point, of gas

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29
Q

What are boiling chips for?

A

ensure uniform heating

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30
Q

Where are boiling chips placed at?

A

inside the round-bottomed flask

31
Q

How is the condenser placed in a distillation setup? Why?

A

placement
Water in bottom, water out top

why?
- Water go against gravity
- ensure cold water fillup as much space condenser
- maximize efficiency of condensation

32
Q

I want to put a rubber stopper on the conical flask to maximize condensation. Can I? Why/Why not?

A

No.

Why Not?
buildup of pressure within the flask, cause explosion

Why will there be a buildup of pressure when the condenser condensed all the gas into liquid anyways?

Some gas may still escape the condenser and end up in the conical flask

33
Q

I have oil and water. How to separate?

A

Using a separating funnel

34
Q

What does miscible mean?

A

mix form homogenous solution

Example:
Petrol and water

35
Q

3 gas dryers

A

Conc. sulfuric acid
Calcium chloride
Calcium oxide

36
Q

What can calcium oxide dry?

A

Hydrogen and Ammonia gases

credits google lol i didn’t know it dry hydrogen

37
Q

What can conc. sulfuric acid dry?

A

Acidic, neutral gases insoluble in water

38
Q

What can calcium chloride dry?

A

anything except conc. sulfuric acid, calcium oxide dried gases

39
Q

What apparatus to use to measure gas? How does the setup look like?

A

Gas syringe

TIP:
- gas syringe use conical flask
- water displacement use measuring cylinder
- downward, upward collection use test tube/gas jar

https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit page 6

40
Q

When to use downward upward collection/displacement of water + their diagrams

A

Downward Collection
- Mr > 30
Upward Collection
- Mr < 30
Displacement of water
- Mr too close, 30
- volume of gas, determined, measuring amt. of water displaced

DIAGRAMS
Downward collection

Upward collection

Displacement of water
https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit PAGE 1

41
Q

I wan collect Gas B that is soluble in water and Mr = 32 how do I do it?

A

Gas syringe

**(rarely will have this kinda qns with gas syringe as collection)

42
Q

ethanol b.p.

A

78deg

78% nitrogen in inhaled, exhaled air, just saying…

43
Q

sublimation vs decomposition

A

sublimation
- no chem. reaction
- change of state
decomposition
- chem. reaction
- new products

44
Q

what causes vaporisation? what is it?

A

vaporisation: conversion of any substance from liquid -> solid state

what causes it: boiling, evaporation

45
Q

is oxygen soluble in water?

A

no

46
Q

is hydrogen, nitrogen soluble in water?

A

no

47
Q

is carbon dioxide, ammonia gas soluble in water?

A

yes

48
Q

does “fluid” consist of solid, liquid or gas?

A

liquid and/or gas

49
Q

what 2 measure time

A

digital, mechanical stopwatch

50
Q

wat 2 measure mass, and SI unit

A

electronic, beam balance

SI: kg

51
Q

wat 2 measure volume, and SI unit

A
  • gas syringe
  • burette
  • pipette
  • volumetric flask
  • measuring cylinder

SI: m^3

52
Q

wat to measure temp. and SI unit

A
  • alcohol thermometer
    SI unit: Kelvin
53
Q

wat to measure length and SI unit

A

metre rule
SI unit: m

54
Q

what does pipette and volumetric flask measure?

A

pipette: accurate fixed smaller volumes
volumetric flask: accurate fixed large volumes

55
Q

Fill in the blanks

smaller particles pass through ___ of filter paper, while bigger particles are retained on it

A

pores

56
Q

what is the liquid collected in distillate after distillation called?

A

distillate

not filtrate

57
Q

why use conical flask as recieving flask for distillation?

A
  • narrow neck, reduce loss of distillate
58
Q

1spot chromatogram vs no spot chromatogram

A

1spot:
pure substance
nospot:
insol. in solvent or
sample dissolved in solvent (if starting line below solvent)

59
Q

from top to bottom, list components of paper chromatography.

A
  • lid
  • solvent front
  • chomatography paper
  • spot
  • starting line
  • solvent

SETUP
https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit page 2

60
Q

why use small amt. of sample in paper chromatography?

A

prevent tailing, smudging of different components,
identify spots easily

61
Q

why have high solvent front but cannot allow solvent front to travel to edge of paper

A

high solvent front
allow all components, separate fully

cannot allow solvent front travel -> edge
- prevents components, being unaccountable
- more accurate -> measure actual distance travel by solvent

62
Q

wat is lid on paper chromatography for?

A

prevent evaporation, solvent

63
Q

wat is chromatography paper for paper chromatography for?

A
  • allow separation, components in sample
64
Q

why starting line above solvent?

A
  • prevent sample, dissolve in solvent
65
Q

advantages of using paper chromatography

A
  • quick, accurate analysis of sample
  • req small amt. of sample
  • separate complex mixture
66
Q

define solute

A

substance which dissolve in liqud, form soln.

67
Q

define solvent, solvent front

A

solvent
liquid in which solute dissolve in

solvent front
frontmost area/end point, solvent travels to

68
Q

3 scenarios where filter funnel used

A
  1. filtration
  2. precipitation reaction
  3. filter excess solid reactant
69
Q

accuracy of apparatus
- burette
- pipette
- measuring cylinder
- Electronic Balance
- ANALOUGE Stopwatch
- DIGITAL Stopwatch
- ALCOHOL Thermometer

A

Burette: +- 0.05cm^3
Pipette: more accurate than measuring cylinder
Measuring Cylinder: +-0.5cm^3
Electronic Balance: +-0.01g
ANALOUGE Stopwatch: +- 0.1s
DIGITAL Stopwatch: +- 0.01s
ALCOHOL Thermometer: +-0.5deg celc

70
Q

How 2 accurately read volume of liquid?

A
  1. Hold container eye level
  2. Read off scale meniscus of liquid

CONCAVE VS CONVEX MENISCUS READING
https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit Page 3

71
Q

Common liquids that have concave, convex mensicus

A

CONCAVE
water
CONVEX
mercury

72
Q

what is a meniscus?

A

surface of liquid, curves at sides of walls, measuring instrument

73
Q

gas drying diagram

A

https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit page 7

Long tube in first.

74
Q

gas diffusion diagram
- hydrogen in gas jar
- air in porous pot

A

https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit page 8

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