Chemistry 1027A/B Study Guide - Midterm Guide: Fractional Distillation, Paper Chromatography, Gas Chromatography

78 views6 pages
What do Crudge Oil, Tacxol & Coloured Markers Have in Common
Key Learning Outcomes :
1. Describe the differences between pure substances and mixtures.
2. Determine whether a given mixture is homogeneous or heterogeneous.
3. Define volatility, solubility, and adsorptivity, and describe the separation techniques that rely on each of
these properties.
Section A : Mixtures & Pure Substances
Mixture : Mixture is 2 or more independent substances that have not reacted chemically with each other
- A mixure is made of little bits of substance mixed together
- A mixture can be separated by physical means
Pure Substance : A sigle type of ateial A sustae a e aythig, does’t hae to e a sigle eleet o
type of molecule, IE honey is a pure substance even though honey is composed of different molecule
Homogeneous Mixture: Mixture where compoents making up mixture and uniformly distirubted thughout., the
composition of the mixture is the same throughout
- There is only one phase of matter observed in a homogeneous mixture
- Cant pick out components, or use simple mchenical means to separate
- Air, sugar water, vodka, detergent
Heterogeneous Mixture : A mixture having a non-uniform composion, the composition varies from one region to
another
- Atleast 2 phases remain seprrate from eachother with clearly identifiable properties
- Can see separate comonents - compenets are not uniform or have lcoalized regions with different
properties
- Concrete, Icecubes in Cola etc
Crude Oil is a Mixture
The mixture has uniform composition and properties consistent with being a
liquid so it is homogeneous
o Homogeneous: Things uniform in appearance and composition
When Refined oil is separated into fractions (also mixtures)
o Fractions: Family of compounds
Taxol Refers to one specific Pure Substance , Its originally isolated
from the bark of pacific Yew trees (Oregon &California Only)
- Bark is not a sustainable resource; Take Pine Needles Small
bit of molecule Isolate in lab- add missing part in lab
- Unlike Oil, bark is a heterogenous mixture
o No Uniformity (appearance), diff composition
Taxol = One Compound i.e Opiod, Morphine, Penicillin
Coloured Market Ink
- Ink is a homogeneous mixture containing one or more dyes, The Dyes can be separated
Common experiment : Paper Chromatography to separate the dyes (Brown,Violet,Green best)
In Class Paper Chromatography: Ethanol + Water, change polarity by mixing (Increase water Increase Polarity)
- Paper used to sepeate materials while liquid is the solvent
Result:: Red, Orange, Blue Shows you cant often ell whats in a mixture till you separate
Chromatography : Science of Seperation
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in
Group Activity : Determing Which are Heterogeneous vs. Homogeneous
Questions : Does it look uniform, if you were to take asample of different spots would it be the sample or different
Section B : Seperation of Mixtures
The separation of substances in a mixture relies primarily on differences in physical properties. 3 important ones
are
- Volatility
- Solubility
- Absorptivity
A.Volatility A measure of how volatile a substance is. Volatile How easily a substance
will vaporise (Evaporpate regularly at room temperature)
- More Volatile equates to a lower boiling point (Volatility increases with temperature)
I.e a very volatile compound would have a lower boiling point
o Evaporation : Increasing heat increases evaporation
Measuring Volatility : Boiling Point, Vapour Pressure Related to atmophseric pressure
- When Vapours pressure = Atmospheric pressure boiling occurs
Examples, when water is 100 degrees, it boils
When Butane (Very Volatile) is contained within a cigarette lighter as
a liquid, when the valve opens the butane vaporizes
Distillation : Used to separate substances based on relative volatility (If substances have
similar volatilities inperfect separation)
Idea : Take a mixture into a container, add heat untill boiling (State of Matter Liquid). As
liquid boils eventually evaporates (Liquid Gas)
Product collected : Distillate, what is formed from distillation. Hihgher volatile liquids
evaporate first different composition 1 second vs 5 minutes in.
Distillation & Producing Alcohol
Foreshots : First Vapours, most volatile(MV liquids evaporate first)
Methanol extremely toxic, lowest Boilng out
Methanol CH3Ch2OH Ethanol CH3CH2CH2OH PROPANOL : As
molecules increase in size, boiling points increase (more bonds to
break)
Heads: Acetone (Nailpolish Remover)
Hearts : Maily Ethaol Cogees “ustaes othe the alohol
you want, give fragrance, odour, flavour
Tails : You combine with Heads ( Acetone) for future creations
Why Distillation : Distillation because ethanol kills yeast (no above
14%)
Take Away Message : Size of the molecule directly affects volatility
(more heat needed to boil molecule)
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Document Summary

What do crudge oil, tacxol & coloured markers have in common. Key learning outcomes : describe the differences between pure substances and mixtures, determine whether a given mixture is homogeneous or heterogeneous, define volatility, solubility, and adsorptivity, and describe the separation techniques that rely on each of these properties. Mixture : mixture is 2 or more independent substances that have not reacted chemically with each other. A mixure is made of little bits of substance mixed together. A mixture can be separated by physical means. Pure substance : a si(cid:374)gle type of (cid:373)ate(cid:396)ial (cid:894)a su(cid:271)sta(cid:374)(cid:272)e (cid:272)a(cid:374) (cid:271)e a(cid:374)ythi(cid:374)g, does(cid:374)"t ha(cid:448)e to (cid:271)e a si(cid:374)gle ele(cid:373)e(cid:374)t o(cid:396) type of molecule, ie honey is a pure substance even though honey is composed of different molecule. Homogeneous mixture: mixture where compoents making up mixture and uniformly distirubted thughout. , the composition of the mixture is the same throughout. There is only one phase of matter observed in a homogeneous mixture.

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
Booster Classes