ch 5- separation and identification of the components of mixtures Flashcards
Solute(n.)
-Solute(n.)=A substance that dissolves in a solvent
Solvent(n.)
-Solvent(n.)=A substance that has a solute dissolved in it
Solution(n.)
-Solution(n.)=The final product when a solute dissolved in a solvent
Solubility(n.)
-Solubility(n.)=The degree to which a solute dissolves in a solvent
Homogeneous(n.)
-Homogeneous(n.)=denoting a process involving substances in the same phase (solid, liquid, orgaseous)
What is an aqueous solution
Aqueous(aq) is the type of solution when a solute is dissolved into water
What solvents dissolve what solutes
(like dissolves like)
What does the degree something dissolves depend on
-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
What is the strongest intermolecular force of non-polar molecules
:Strongest intermolecular force between non-polar molecules=Dispersion forces
What are the requirements for a molecule to undergo hydrogen bonding
: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
What intermolecular force do polar molecules undergo
: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
What do polar solute dissolve in
-Polar solutes will dissolve in polar solvents
What do non-polar solutes dissolve in
-Non-polar solutes will dissolve in non-polar solvents
What is FONCl, what does it stand for, and why is it important to remember
FONCl=
F=fluorine
O=oxygen
N=Nitrogen
Cl=Chlorine
FONCl is the order of decreasing electronegativity
Examples of polar substances
Water, H2O
Methanol, CH3OH
Methanolic acid, HCOOH
Ammonia, NH3
Vitamin C, C6H8O6
Lactose, C₁₂H₂₂O₁₁
Examples of non polar substances
Cyclohexane, C6H12
Ethene, CH2CH2
Benzene,
Oxygen, O2
Vitamin D, C28H44O Not sure about this
Triglyceride, C27H50O6. Not sure about this
-Mixtures(n.)
-Mixtures(n.)=Two or more substances not chemically combined
-Chromatography(n.)
-Chromatography(n.)=A technique used to separate mixtures
-Stationary phase(n.)
-Stationary phase(n.)=The phase that does not move e.g. paper
-Mobile phase(n.)
-Mobile phase(n.)=A solvent or mixture of solvents that move across the stationary phase.
How does chromatography separate mixtures
-Chromatography is a technique that separates mixtures depending on the relative solubility of each substance in a solvent.
What is the stationary and mobile phase examples
: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.
What is the origin
-Origin=where mixture is added + origin is drawn in pencil-graphite which doesn’t move
What is the RF value
-Rf value=distance of component travelled/distance of solvent front
Origin(n.)
-Origin(n.)=The starting point for chromatography where the mixture is added to the stationary phase
Solvent front(n.)
-Solvent front(n.)=The end point for a chromatogram where the solvent reaches
How does thin layer chromatography work
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.
HPLC(n.)
-HPLC(n.)=High performance liquid chromatography - a technique used in which the mobile phase is pumped through a tightly pack stationary phase under pressure
Eluent(n.)
-Eluent(n.)=Solvent fluid that moves through a chromatography system
How does a HPLC machine work
-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
The parts of a HPLC machine
-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
-Retention time(n.)
-Retention time(n.)=Time taken for a component to pass through a HPLC column
-Peak area(n.)
-Peak area(n.)=The area enclosed between the peak and the baseline on a chromatogram
What does all the data on a chromatogram from a HPLC machine represent
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.
Is using a HPLC machine grant scientist with qualitative or quantitative data.
HPLC is a technique that is both quantitative and qualitative.
