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chem unit 1 > ch 5- separation and identification of the components of mixtures > Flashcards

ch 5- separation and identification of the components of mixtures Flashcards

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1
Q

Solute(n.)

A

-Solute(n.)=A substance that dissolves in a solvent

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2
Q

Solvent(n.)

A

-Solvent(n.)=A substance that has a solute dissolved in it

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3
Q

Solution(n.)

A

-Solution(n.)=The final product when a solute dissolved in a solvent

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4
Q

Solubility(n.)

A

-Solubility(n.)=The degree to which a solute dissolves in a solvent

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5
Q

Homogeneous(n.)

A

-Homogeneous(n.)=denoting a process involving substances in the same phase (solid, liquid, orgaseous)

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6
Q

What is an aqueous solution

A

Aqueous(aq) is the type of solution when a solute is dissolved into water

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7
Q

What solvents dissolve what solutes

A

(like dissolves like)

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8
Q

What does the degree something dissolves depend on

A

-The degree in which something dissolves in the non polar part or polar part depends on its relative solubility=Solubility is not all or none, it is a range

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9
Q

What is the strongest intermolecular force of non-polar molecules

A

:Strongest intermolecular force between non-polar molecules=Dispersion forces

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10
Q

What are the requirements for a molecule to undergo hydrogen bonding

A

:If polar molecule has F,O, or N bonded to hydrogen, it can undergo hydrogen bonding with a F,O,or N on an adjacent molecule

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11
Q

What intermolecular force do polar molecules undergo

A

:polar molecules undergo dipole-dipole attraction with other polar molecules

:If polar molecule has F,O, or N bonded to hydrogen, it can undergo hydrogen bonding with a F,O,or N on an adjacent molecule

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12
Q

What do polar solute dissolve in

A

-Polar solutes will dissolve in polar solvents

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13
Q

What do non-polar solutes dissolve in

A

-Non-polar solutes will dissolve in non-polar solvents

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14
Q

What is FONCl, what does it stand for, and why is it important to remember

A

FONCl=
F=fluorine
O=oxygen
N=Nitrogen
Cl=Chlorine

FONCl is the order of decreasing electronegativity

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15
Q

Examples of polar substances

A

Water, H2O
Methanol, CH3OH
Methanolic acid, HCOOH
Ammonia, NH3
Vitamin C, C6H8O6
Lactose, C₁₂H₂₂O₁₁

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16
Q

Examples of non polar substances

A

Cyclohexane, C6H12
Ethene, CH2CH2
Benzene,
Oxygen, O2
Vitamin D, C28H44O Not sure about this
Triglyceride, C27H50O6. Not sure about this

17
Q

-Mixtures(n.)

A

-Mixtures(n.)=Two or more substances not chemically combined

18
Q

-Chromatography(n.)

A

-Chromatography(n.)=A technique used to separate mixtures

19
Q

-Stationary phase(n.)

A

-Stationary phase(n.)=The phase that does not move e.g. paper

20
Q

-Mobile phase(n.)

A

-Mobile phase(n.)=A solvent or mixture of solvents that move across the stationary phase.

21
Q

How does chromatography separate mixtures

A

-Chromatography is a technique that separates mixtures depending on the relative solubility of each substance in a solvent.

22
Q

What is the stationary and mobile phase examples

A

:The stationary phase doesn’t move=It might be a piece of paper or the inside surface of a tube.
:The mobile phase moves over the stationary phase=This could be a solution that passes over a piece of paper, or a gas or liquid that passes through a tube.

23
Q

What is the origin

A

-Origin=where mixture is added + origin is drawn in pencil-graphite which doesn’t move

24
Q

What is the RF value

A

-Rf value=distance of component travelled/distance of solvent front

25
Q

Origin(n.)

A

-Origin(n.)=The starting point for chromatography where the mixture is added to the stationary phase

26
Q

Solvent front(n.)

A

-Solvent front(n.)=The end point for a chromatogram where the solvent reaches

27
Q

How does thin layer chromatography work

A

Key takeaway=
-Paper or coated glass is the stationary phase. A solvent is the mobile phase

Deep dive=
-The mixture is placed on the origin
-The solvent moves from under the origin across the stationary phase towards the solvent front
-Substances that are more attracted to the stationary phases than the mobile phase absorb to the stationary phase.
-A series of absorptions/desorptions take place
-The substance most soluble in the mobile phase moves the fastest over the stationary phase.

-A standard is a known substance used to identify the relative solubility of the substances in the mixture undergoing the process of chromatography.

28
Q

HPLC(n.)

A

-HPLC(n.)=High performance liquid chromatography - a technique used in which the mobile phase is pumped through a tightly pack stationary phase under pressure

29
Q

Eluent(n.)

A

-Eluent(n.)=Solvent fluid that moves through a chromatography system

30
Q

How does a HPLC machine work

A

-HPLC is based upon the repeated adsorption and desorption of components between the stationary and mobile phase.1Components which are more strongly adsorbed to the stationary phase will spend more time stationary compared to those which are more strongly desorbed into the mobile phase.2Therefore, the components experience different rates of motion through the column, leading to varying retention times.3

31
Q

The parts of a HPLC machine

A

-The stationary phase is a solid packed into a column
-The mobile phase is a solvent fluid that moves through the column
-The pump uses pressure to force the mobile phase to move over the stationary phase
-The sample to be analysed is injected into the machine above the column
-The eluent is the solvent that leaves the chromatography machine

32
Q

-Retention time(n.)

A

-Retention time(n.)=Time taken for a component to pass through a HPLC column

33
Q

-Peak area(n.)

A

-Peak area(n.)=The area enclosed between the peak and the baseline on a chromatogram

34
Q

What does all the data on a chromatogram from a HPLC machine represent

A

Analysing experimental data(of chromatogram)=
:Examine a chromatogram from an HPLC machine
:The number of peaks represents the number of components in the mixture
:The retention time in HPLC is equivalent to the Rf value in paper and TLC
:The retention time under the same conditions can be used qualitatively to identify a substance
:The peak area(area under the curve) corresponds to the concentration of the substance quantitatively when compared to a calibration curve run under the same conditions.

35
Q

Is using a HPLC machine grant scientist with qualitative or quantitative data.

A

HPLC is a technique that is both quantitative and qualitative.

chem unit 1 (10 decks)

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