ch 5- separation and identification of the components of mixtures

Question 1

Solute(n.)

Answer 1

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

Question 2

Solvent(n.)

Answer 2

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

Question 3

Solution(n.)

Answer 3

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

Question 4

Solubility(n.)

Answer 4

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

Question 5

Homogeneous(n.)

Answer 5

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

Question 6

What is an aqueous solution

Answer 6

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

Question 7

What solvents dissolve what solutes

Answer 7

(like dissolves like)

Question 8

What does the degree something dissolves depend on

Answer 8

-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

Question 9

What is the strongest intermolecular force of non-polar molecules

Answer 9

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

Question 10

What are the requirements for a molecule to undergo hydrogen bonding

Answer 10

: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

Question 11

What intermolecular force do polar molecules undergo

Answer 11

: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

Question 12

What do polar solute dissolve in

Answer 12

-Polar solutes will dissolve in polar solvents

Question 13

What do non-polar solutes dissolve in

Answer 13

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

Question 14

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

Answer 14

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

FONCl is the order of decreasing electronegativity

Question 15

Examples of polar substances

Answer 15

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

Question 16

Examples of non polar substances

Answer 16

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

Question 17

-Mixtures(n.)

Answer 17

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

Question 18

-Chromatography(n.)

Answer 18

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

Question 19

-Stationary phase(n.)

Answer 19

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

Question 20

-Mobile phase(n.)

Answer 20

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

Question 21

How does chromatography separate mixtures

Answer 21

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

Question 22

What is the stationary and mobile phase examples

Answer 22

: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.

Question 23

What is the origin

Answer 23

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

Question 24

What is the RF value

Answer 24

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

Question 25

Origin(n.)

Answer 25

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

Question 26

Solvent front(n.)

Answer 26

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

Question 27

How does thin layer chromatography work

Answer 27

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.

Question 28

HPLC(n.)

Answer 28

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

Question 29

Eluent(n.)

Answer 29

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

Question 30

How does a HPLC machine work

Answer 30

-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

Question 31

The parts of a HPLC machine

Answer 31

-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

Question 32

-Retention time(n.)

Answer 32

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

Question 33

-Peak area(n.)

Answer 33

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

Question 34

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

Answer 34

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.

Question 35

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

Answer 35

HPLC is a technique that is both quantitative and qualitative.