Legit na org chem lab Exercise 1-3

Flavin

Anthocyanin in red cabbages

Used as indicator in pH paper

pH is defined as the __________ of the H+ ion concentration of a substance

pOH is defined as the ________ of the OH– ion concentration of a substance

negative logarithm

soda lime test is limited for organic compounds with ______ group only, nitro and azo compounds cannot be detected by this test

amino

acid strengths are normally given using _______ (_____ = –log Ka)

pKa values, pKa

Other name for stoichiometry

Equivalence point

pH meter

More accurate than pH paper

Has a probe that send electrical signals to the meter, then it gets interpreted on the screen

pH meter

the glass pH probe contains two electrodes: a ____________ (that contains a pH 7 buffer solution), and a reference electrode (that usually contains saturated potassium chloride solution)

sensor electrode

reference electrode (that usually contains ____________________ solution)

saturated potassium chloride

Silver chloride (AgCl)

Calomel

pH paper measures the pH of the solution by changing its color depending on the

concentration of H+ and OH– ons

Hard to detect because they do not ionize

Nitrogen, halgoen, sulfur

these elements must be converted first into inorganic ions before proceeding to qualitative analysis → done by fusing the organic compound with the ________

sodium metal

In pH meter, the _________________ is measured by the meter and then converts it to pH value

voltage of this electrical flow

Conversion of organic compound to inorganic compound

Lassaigne’s sodium fusion test

In beilstein test, ________ does not yield a positive result

fluorine

if the organic compound is in the form of ___________, heating it with soda lime (NaOH and CaO) will liberate ammonia (NH3) gas (characteristic pungent ammonia odor)

amino nitrogen (–NH2)

if the organic compound is in the form of amino nitrogen (-NH2), heating it with _________________ will liberate ammonia (NH3) gas (characteristic pungent ammonia odor)

soda lime (NaOH and CaO)

soda lime test is limited for organic compounds with amino group only, _____________________ compounds cannot be detected by this test

nitro (-NO2 ) and azo (-N=N-)

Sodium extract

Lassaigne’s extract

the Lewis structure of water shows that it a ________________, therefore acting as the Lewis base

non-bonding pairs of valence electrons

elements that can be commonly found among organic compounds include:

C, H, O, N, S, P, and Halides group

can give a satisfactory results in identifying elements in organic compounds using qualitative chemical reagents

systemic approach

qualitative chemical tests highly rely on _______________ through observation of test results

organoleptic approach

CO2 is detected by

lime water

Calcium Hydroxide

Lime water

H2O is detected by

anhydrous cupric sulfate

CO2 reacts with Ca(OH)2 forming

CaCO3 and H2O

an organic halogen compound dipped in a

copper wire will yield a _________________ when burned

green-colored flame

the copper oxide from the copper wire formed

upon heating, reacts with the halogen from the

organic compound to form ____________ which

is responsible the color of the flame

cupric halide

In silver nitrate test, the silver halide yields a __________________, confirming the presence of a halogen

white to light yellow precipitate

In lead acetate test, albumin contains the amino acid _________

cysteine

cysteine is an amino acid with a ___________

sulfhydryl group

In lead acetate test, __________ the solution causes the breaking of the polypeptide chain

heating

In ferrox test, oxygen can be detected using ferrox paper or _______________

iron (III) hexathiocyanatoferrate

Iron (III) hexathiocyanatoferrate dissolves in the presence of oxygen giving off a __________________ color of the solution

red to reddish-purple

acid is any species that can increase the concentration of hydrogen ions (protons) in an aqueous solution

base is any species that can increase the concentration of hydroxide ions, OH– in an aqueous solution

Arrhenius Theory

In Bronsted Lowry theory an acid is any species that can __________ a proton (H+)

donate

In Bronsted Lowry theory a base is any species that can _______ a proton

accept

in a Brønsted-Lowry acid-base reaction, a ______________ is a species formed after the base accepts a proton, while a conjugate base is the species formed after an acid donates its proton

conjugate acid

____________ (eg. inorganic acids), react almost completely with water

stronger acids

_____________ (eg. acetic acid) react only slightly

weak acids

K_a

Acidity constant

gives the exact strength of a given acid in water

Acidity constant

__________ is a species that can accept a pair of non-bonding electrons

Lewis Electron Pair Theory - Acid

________ is a species that can donate a pair of non-bonding electrons

Lewis Electron Pair Theory - Base

negative logarithm in the definition of pKa indicates an

______________ between Ka and pKa

inverse relationship

the Lewis structure of ________ shows that it has a non-bonding pairs of valence electrons, therefore acting as the Lewis base

water

the __________ suggests that it has free orbitals that can accept pairs of non-bonding electrons donated by the water molecules, thereby acting as the Lewis acid

aluminum ion (Al3+)

the temperature at which the vapour pressure of the substance is equal to the atmospheric pressure above it

Boiling point

When the temperature in which the vapor pressure is equal to atmospheric pressure

Boiling point

Boiling point is when the temperature in which the ______________ is equal to atmospheric pressure

vapor pressure

a liquid at a higher pressure has ______________.

a higher boiling point

the lower the boiling point, _________

the more highly volatile the substance

Compound will exist as gas if…

it has a low normal boiling point.

Compound will exist as liquid or solid if…

if it has higher normal boiling point

Boiling point is affected by …..

Intermolecular forces

Van Der Waals Dispersion Forces are weak intermolecular attraction formed by ___________ of molecules

induced polarization

Van Der Waals Dispersion forces is commonly observed among ______________ and occurs only within ____________ in between molecules

hydrocarbon groups, short distances

occurs among partially ionic or polar molecules

Dipole-dipole interaction

Dipole-dipole interaction have molecules that contain an _______________ due to the two poles of the molecule: one end is partially negative while the other end is partially positive

asymmetrical charge

formed between partially positive hydrogen (H+) and an adjacent electronegative atom which bears a partial negative charge

Hydrogen Bond

Hydrogen Bond is formed between _____________________ and _____________________ which bears a partial negative charge

partially positive hydrogen (H+) and an adjacent electronegative atom

intermolecular hydrogen bonds tend to _____________ of an organic compound

rise boiling point

takes place between molecules having opposite charges and involves an electrostatic interaction between the two opposite charges

Ionic bond

takes place between molecules having opposite charges and involves an electrostatic interaction between the two opposite charges.

Ionic bond

the functional groups which most easily ionize are ______ and ___________, such as the reaction of ammonia (NH3) with a carboxylic acid (carboxylate ion)

amines, carboxylic acid

Factors that can affect boiling point

• Length of the carbon chain

boiling point (_) as the number of carbon atoms (_)

Increases

boiling point (_) in the presence of branching

Decreases

boiling point (_) as the polarity of the substance (_)

Increases

boiling point (_) in the presence of non-volatile impurities

Increases

boiling point (_) in the presence of volatile impurities

Decreases

the temperature at which a solid compound is directly converted to its liquid state

Melting point

a _______________ compound has a sharp melting point and it completely melts within a narrow range of temperature NMT ___________.

pure crystalline, 0.5-1°C

if a compound melts over a very narrow range, it is assumed that the compound tested is ________

relatively pure

the presence of __________, and especially hydrogen bonding, leads to a higher melting point of compounds

polarity