O Chem Lab 235

Front 1

Absorption

Back 1

The drawong up of a liquid through a mass; permeating the bulk of the absorbing material

Front 2

Acidic

Back 2

Having a ph less than seven litmus paper pink

Front 3

Adsorption

Back 3

Special kind absorption restrocted to adhesion of material to the surface of the bodies. Attached either by chem bonds or vander whal forces

Front 4

Alkaline or basic

Back 4

Ph greater than seven litmus paper blue

Front 5

Anhydrous

Back 5

With out water all water has been removed from substance so if comes in contact with water it will absorb quite readily

Front 6

Aqueous phase

Back 6

Liquid layer in which water is the solvent (density = ~1g/ml)

Front 7

Azeotrope

Back 7

Mixture of 2 or more substances that distills at constant temp and w constant composition even tho seperately components have diff bps. Usually occurs when intermol interactions like h bonding take place

Front 8

Benchtop extraction

Back 8

Process of recovering a desired substance that has been accidentally spilled on Benchtop by scraping up substance and then purifying by recrystallization or soaking up a solid or liquid substance with cotton that has been saturated with suitable solvent and then extracting from cotton with more solvent.

Front 9

Boiling chip

Back 9

Granules of porous alundum which release bubbles of entrapped air to a soln as it is being heated. These bubbles provide a path by which the vapour of boiling liquid can be smoothly led to surface and released. Can never be used twice and never be added to hot soln near bp since violent frothing will result.

Front 10

Boiling point

Back 10

Temp at which vapour pressure of liquid is equal to atmospheric pressure. Bp is constant for pure substance.

Front 11

Bumping

Back 11

The sudden violent surge of vapour breaking from surface of a liquid. If liquid is free of trapped air pockets bubbles do not form readily and temp of liquid may rise above boiling.point. liquid becomes super heated and when a bubble does form its internal pressure rapidly exceeds external pressure and bumping occurs.can be prevented w boiling chips and by stirring.

Front 12

Capillary action

Back 12

Phenomenom of elevation or depression and of adhesion and cohesion of a liquid observed in a thin tube which is placed in a liquid due to surface tension

Front 13

Carcinogenic

Back 13

Cancer causing agent which could cause death or permanent damage as a result of repeated of exposure over a long period of time.

Front 14

Catalysis

Back 14

The acceleration or promotion of a chem rxn by a reagent or catalyst which itself remains unchanged.

Front 15

Celite

Back 15

White coarse powder made up of diatomaceous earth also known as filteraid. Used during filtration to prevent small particles from passing thru filter paper.

Front 16

Condensate

Back 16

Liquid that results when a gas is cooled.

Front 17

Condensation

Back 17

The process by which matter changes from gaseous to a liquid state

Front 18

Condenser

Back 18

Apparatus in which gases are cooled until they become liquid. Direction of water flow is always against gravity.

Front 19

Corrosive

Back 19

Having the ability to cause immediate damage upon contact.

Front 20

Distillation

Back 20

Two part process on which 1. liquid is boiled thereby converting it to vapour and 2. the vapour is then recondensed to a liquid and collected in a diff container from original one

Front 21

Distillate

Back 21

The condensed liquid obtained from distillation

Front 22

Drying agent

Back 22

An inorganic salt that can form hydrates used to.remove small.amounts of water that have been absorbed by organic solvents.

Front 23

Emulsion

Back 23

A finely dispersed suspension of one liquid layer in another which happens when dissolved materials in these liquids cause the mutual solubility of the two.layers to increase.often appaears as a foamy layer between two normally immiscible liquids.

Front 24

Extraction

Back 24

Process of removing a desired substance from a soln or solid mixture based on diff in solubility.

Front 25

Filtrate

Back 25

The liquid which passes thru a filter

Front 26

Flammable

Back 26

Having the ability to burn

Front 27

Fractionating column

Back 27

Glass tube having a large internal surface area upon which a gas can condense and evaporate many times before reaching the end of the column.

Front 28

Hygroscopic hydroscopic?

Back 28

Attracts water

Front 29

Ice bath

Back 29

A mixture of ice and water with a higher % of water. Much more effecient than cooling than ice byself (increases surface area)

Front 30

Immiscible

Back 30

Substances unable to be blended; usually liquids like oil and water. Diff densities (seperate)

Front 31

Inflammable

Back 31

Easily set on fire.

Front 32

Labeling

Back 32

The following info where applicable should be included on official label of a sample that has been prepared : exp name section locker number, date of preparation, name and structure of compound, weight or yield in g (and % yield), any physical constants that were measured (not literature value)

Front 33

Limiting reagent

Back 33

The reagent which is present in lowest amount according to stoichiometeric relationship of the rxn.

Front 34

Melting.point.

Back 34

Temp at which solid and liquid phases of substance are in.equilibrium under external pressure of one atmosphere. Melting point usually consists of two temps. 1st is at which 1st drop.of liquid appears amongst crystals

2nd is at which whole mass is liquid. Purer compound the narrower the mp range. Unpure compounds=depressed and widened range.

Front 35

Miscible

Back 35

Liquids capable of being mixed in all.proportions to form homogenous substances

Front 36

Mol percent

Back 36

The number of.mols of substance in question divided by total number of mols of.all substances in the mixture.

Front 37

Mother liqour

Back 37

The soln that remains after a crystallization. Consists of recrystallization solvent saturated with dissolved solute.

Front 38

Mull

Back 38

Mixture of finally ground solid sample in an inert carrier liquid such as nujol. This is one method used to.prepare a solid sample to.allow you to.take an infared spectrum on.it.

Front 39

Norit

Back 39

Activated charcoal which can be used to absorb small.amounts of.coloured soluble impurities from a soln.

Front 40

Organic phase

Back 40

The liquid layer in which organic liquid is solvent ie ether.

Front 41

Oxidation

Back 41

The chem rxn of oxygen or oxidizing agent with free elements and with compounds. This may result in 1. An increase in number of O molecules within a compound 2. An decrease in number of H molecules or 3. The loss of e- to an oxidizing agent. An oxidizing agent is reduced in oxidation.

Front 42

Percentage recovery

Back 42

Final weight divided by initial weight times 100 . often used during recrystallization to determine how much was lost.

Front 43

Percentage yield

Back 43

Actual yield divided by theoretical yield times 100.

Front 44

pH

Back 44

Log [h3o+] a measure of the concentration of h ions in soln. Lless than seven is acidic. Greater than seven is basic.

Front 45

Purification

Back 45

The process of removing impurities from a desired substance. Can be accomplished by such processes as recrystallization extraction and distillation.

Front 46

Quantitative transfer

Back 46

The transfer of a substance from.one container to another so that none of substance is left behind in original container. Usually axcomplished by rinsing 1st container several times with suitable solvent and adding all rinses to 2nd container.

Front 47

Recrystallize

Back 47

Purifying of a solid substance by dissolving material in.min amount of hot solvent and then allowing soln to cool slowly. As soln cools solubility of substances in solvent decreases and thus crystals fall out of soln.

Front 48

Reduction

Back 48

Opp of oxidation. Chem rxn bt reducing agent and free elemnts or compounds. May result in 1. Decrease in O in compound 2. Imcrease in number of h 3. A gain of e- to compound supplied by reducing agent. Reducing agent is oxidized during reduction.

Front 49

Reflux

Back 49

Process whereby heated liquid evaporates enters a condenser where it is allowed to cool to.liquid state and then flow.back to.original boiling soln. Good reflux is 1 drop/sec off end of condenser.

Front 50

Refractive index

Back 50

The ratio.of sin of angle of incidence to the sin of angle of refraction; Measure of.retracting quality of a medium. The ratio of velocity of light in air to the velocity of light in another medium. This meaurement is dependent upon temp and the wavelength of light. Since they are temp dependent. Conversion is t1= t obs + (0.00045)(tobs-t1)

Front 51

Residue

Back 51

That which remains left behind. The remainder. Usually the solid that remains after filtration

Front 52

Rf

Back 52

The distance traveled by a solute on tlc plate divided by the distance traveled by the solvent on the same plate. Not a physical constant for a solute since it varies with solvent used, thickness of plate, and even the relative amount of substance spotted.

Front 53

Rheostat

Back 53

An adjustable resistance for regulating electric current. Here it is used to regulate the temp of the thermowells since they have no regulating device.

Front 54

Saponification

Back 54

The making of soap. The alkaline hydrolysis of a fat.

Front 55

Saturated

Back 55

1. An inorganic compound it indicates that there are no double or triple bonds or rings.

2.in a soln it indicates that under ordinary temp and pressure cond the max amount of solute has been dissolved.

Front 56

Schlierien lines

Back 56

Streaks or wavy lines in a soln indicating regions of diff densities usually indicating something is dissolving.

Front 57

Scratching

Back 57

Using roughened end of glass rod to pull a little of recrystallization solvent above the surface of a liquid while scratching the rod against the side of the container to give a rough area for the first crystal to form.

Front 58

Seeding

Back 58

Placing a seed or pure crystal of a substance in a saturated soln of compound to start the growth of the crystal lattice.

Front 59

Slurry

Back 59

A suspension of fine solid particles in a liquid.

Front 60

Solubility

Back 60

The amount of a solute that will dissolve in a set volume of solvent at a given temp. This is a temp dependent variable.

Front 61

Solute

Back 61

The dissolved substannce in a soln

Front 62

Solvent

Back 62

A liquid capable of dissolving a substance.

Front 63

Solvent pair

Back 63

2 or more miscible solvents which when added together form a mixture having the appropriate properties for recrystallization. One usually dissolves compound very well while other dissolves compound poorly or not at all.

Front 64

Streaking

Back 64

Streaking of a substance along a tlc plate. Usually occurs if too much of the initial material is spotted on the plate or the material is very polar and thus more attracted to plate than developing solvent and consequently very difficult to move up the plate. Latter case can usually be minimized by the addition of a few drops of acidic acid..or some polar liquid to the developing solvent to increase its polarity.

Front 65

Successive extractions

Back 65

Taking your total volume of extracting medium and splitting it into several portions and adding each portion to a seperatory funnel containing an immiscible solvent mixing and removing this portion of extracting medium before adding the next portion. This ensures getting the best possible separation of components in a mixture.

Front 66

Successive washes

Back 66

A series of washes of either a solid or liquid sample in which each individual wash is removed from the system.before the next one is added. Washes remove undesirable products.

Front 67

Tailing

Back 67

Same as streaking.

Front 68

Theoretical yield

Back 68

Maximum weight of a substance that could be produced in a run based upon the amounts of starting material used.

Front 69

Tlc thin layer chromatography

Back 69

Procedure used to analyze a mixture by separating out its constituents by means of selective adsorption from a soln onto an active surface of finely divided solids. This partitioning process is based upon differences in polarity.

Front 70

Turbidity

Back 70

Cloudiness in a soln usually caused by immiscible compounds.

Front 71

Unsaturated.

Back 71

Opp of saturated. Double triple bond or rings exist. Or a soln in which more solute can be dissolved.

Front 72

Vaporization

Back 72

The process of changing to a gas from a liquid to a solid

Front 73

Volatile

Back 73

Tending to evaporate under ordinary temp and pressure conditions.

Front 74

Washing

Back 74

Removal of unwanted materials from desired materials by rinsing them with a suitable solvent.

Front 75

Actual yield

Back 75

The weight of substance that has been produced.