ORGMED LAB 8: ETHANOL

give synonyms of ethyl alcohol

ethanol
grain alcohol
drinking alcohol
alcohol

give chemical formula of ethyl alcohol

C2H6O

ethanol is (CLOUDY OR VIVID / CLEAR OR COLORLESS)

clear or colorless

ethyl alcohol has a ______ odor

wine-like

spgr of ethyl alcohol:

____________ at _____

0.7892 at 10C

give boiling point of ethyl alcohol:

___ C (___F)

78.32 C (172.81 F)

give melting point of ethyl alcohol:

_____ C (____F)

-114.1 C (-173.45 F)

name this structure:

ethyl alcohol

Ethyl alcohol is one of the most commonly used __________ or ________ for many years

antiseptics or disinfectants

a use of ethyl alcohol in which its purpose is to kill or inhibit growth of microbes on living tissues

antiseptics

a use of ethyl alcohol in which its purpose is to kill or inhibit growth of microbes on inanimate objects

disinfectants

ethyl alcohol acts by __________ and ____________ proteins within the _______________ of microorganisms.

this causes disruption of the ______________ of the microbes, ultimately leading to _________ and ______

denaturing and coagulating proteins
within the cell walls and membranes

membrane
cell lysis and death

the length of the aliphatic carbon chain in an alcohol (DIRECTLY / INVERSELY) influences its bactericidal effectiveness, up to____# carbons only.

directly influences
8 carbons

If an alcohol molecule contains 9 or more carbons, they are considered as _____________, in which are _______ liquids

higher alcohols
viscous liquids

higher alcohols tend to be (MORE / LESS ) soluble and have (LOWER / HIGHER) boiling points compared to shorter-chain alcohols due to (INCREASED / DECREASED) molecular forces

less soluble
higher BP
due to increased molecular forces

SAFE bactericidal effect of ethanol at conc between:
_________________

60-85%

For 60%–70% ethanol, exposure times of ______ are necessary

≥5 min

For 80-85% ethanol, exposure times of ______ is effective

≤0.5 min (below 30secs)

Ethanol's primary sources are _________ and _______

sugars and starches

Ethanol is primarily derived from crops like:

_________ (CN) + ____________ (SN)
_________ (CN) + ____________ (SN)
_________ (CN) + ____________ (SN)
_________ (CN) + ____________ (SN)

sugar cane (Saccharum officinarum)
sugar beets (Beta vulgaris)
corn (Zea mays)
wheat (Triticum aestivum)

Ethanol is COMMONLY produced through hydration of _______

ethene

ethene when hydrated, undergoes an _______ reaction with _______ as catalyst to produce ethanol

addition reaction
phosphoric acid

other known method of producing ethanol: ________

fermentation

_____________ (SN) is an example of microorganism that conver carbohydrates into ethanol and carbon dioxide through the (AEROBIC / ANAEROBIC) respiration

Saccharomyces cerevisieae
anaerobic respiration

the ethanol produced from fermentation then undergoes ________ to increase its concentration and remove byproducts

distillation

IN THE 1ST STEP OF FERMENTATION:

A _____ molecule is broken down via ______, yielding ___# _______ molecules.

glucose; via glycolysis

2 pyruvate

IN THE 2ND STEP OF FERMENTATION:

The two pyruvate molecules are broken down, yielding ___# _______ and giving off _____# molecules of carbon dioxide.

2 acetaldehyde
2 carbon dioxide

IN THE 3RD STEP OF FERMENTATION:

The two molecules of ________ reduces the two acetaldehyde molecules to ____# molecules of ethanol.

NADH
2 ethanol

Ethanol, undergoing complete combustion, will yield an (ENDOTHERMIC / EXOTHERMIC) reaction

exothermic

give the reaction of ethanol undergoing complete combustion

C2H5OH + 3O2 → 2CO2 + 3H2O + heat

when undergoing oxidation, ethanol first produces __________ (_______), and then with further oxidation, forms __________ (_______)

acetaldehyde (ethanal)
acetic acid (ethanoic acid)

when undergoing oxidation, the solution color of ethanol changes from ____________ to ________

orange to green

the orange color of ethanol solution is characteristic of the ________ ion

dichromate(VI) ion

as ethanol undergoes oxidation and thus changing color, the green color is characteristic of ________ ion

chromium (III) ion

Esterification of ethanol involves a reaction with a ______, typically in the presence of a ______ like _______, to produce an __________ and ______

carboxylic acid
catalyst; sulfuric acid
ester and water

_______ is the sweet and fruity-smelling ester produced when ethanol undergoes esterification

ethyl ethanoate

_________ can be used as a substitute for ethanol, with similar antiseptic properties.

isopropyl alcohol

isopropyl alcohol is aka ________

2-propanol

name this structure:

isopropyl alcohol

Put the following steps in the correct order by writing the appropriate procedure step number (1–9) in each blank.

_____ Add 20 ml of nutrient solution (which contains 0.55 g of yeast) for fermentation.
_____ Weigh the product and compute for the percentage yield.
_____ Shake the mixture thoroughly and attach a bent tube, fitted to a stopper for the purpose of bubbling the evolved carbon dioxide in lime water.
_____ Attach a water condenser, distill the mixture and collect 3 ml and 7 ml fractions separately.
_____ Place a cotton swab on top of the test tube.
_____ Dissolve 10 g of glucose in 140 ml of water in a 250-ml Erlenmeyer flask.
_____ Lead the bent tube into the test tube which contains 10–15 ml of lime water.
_____ Do not shake at the end of fermentation. Decant the liquid into a 125-ml distilling flask.
_____ Allow the mixture to stand for one full week at room temperature.

2
9
3
8
5
1
4
7
6