Mod 7 Flashcards

Question

esters

Answer 1

add carboxylic acid to alcohol and heat in a water bath then put in cold water to cool and smell it H from alcohol combines with oh from carboxylic acid and makes water, with the c=o part of ester being from carboxylic acid alcohol named first, replace ol with yl carboxylic acid second, replace oic acid with anoate

Answer 2

Lucas test--> lucat reagent is zinc chloride mixed with conc hcl tertiary --> turbidity immediately secondary --> turbidity in 1 to 10 mins primary --> no turbidity

Answer 3

oh bond is polar and co bond is polar but not as polar as oh so cannot form hydrogen bonding as length of carbon chain increases, bp/mp increases as molar mass increases and dispersion forces increase alcohols have higher boiling point that corresponding alkanes as they are capable of dipole dipole and h bonding whereas alkanes arent as length of carbon chain increases from 1-8 difference in bp from alkane and alcohol decreases as less proportion of molecule remains polar (dispersion force dominates)

Answer 4

different mp/bp due to accessibility of oh group bp/mp decreases from primary secondary tertiary oh crowding hinders formation of h bonding (the oh bonds are less accessible)

Answer 5

shorter chain alcohols mainly can act as a universal solvent due to their non-polar hydroxyl group and their polar alkyl group Alcohols dissolve more readily in polar solvents than alkanes, but less reading in non-polar solvents than alkanes length of chain increases, solubility in polar decreases (non polar alkyl chains associate with each other more)

Answer 6

dipole dipole forces with c=o bonds (no H bonding) weaker bonds than alcohols as they have oh h bonding polarity gives solubility in water and decreases as chain length increases (less than alcohols due to no h bonding)

Answer 7

2 highly electronegative oxygen atoms and are very polar has all 3 types of bonding highly soluble in water (esp shorter chains) decreases when chain length increases as non polar alkyl dominates high boiling points weak acids more alkyl groups decreases acidity

Answer 8

weaker intermolecular forces than alcohols and carboxylic acids soluble in water typically short chained has hydrogen bonding but n-h hydrogen bonding less than o-h as n is less electronegative order of boiling points: tertiary

Answer 9

strongest intermolecular forces due to unique bonding geometry and extensive hydrogen bonding very high boiling points h bonding between n-h of one molecule and c=o of adjacent molecule amides soluble in water but decreases when chain length, molecular mass and dispersion forces increase neutral

Answer 10

ethyl butanoate --> pineapple octyl ethanoate --> orange pentyl ethanoate --> pear and banana ethyl methanoate --> lemon, rum ethyl heptanoate --> apricot methyl butanoate --> apple

Answer 11

2 polar bonds c-o c=o so dipole dipole and dispersion but NO H BONDING lower bp than alcohols and carboxylic acid it is made from poor solubility in water (lack of h bonding as water produces h bonding) good solubility in non-polar as chain length increases, dispersion forces increase and bp increases as chain length increases, solubility in water decreases as hydrophobic alkyl chain dominates

Answer 12

condensation rxn requires conc h2so4 catalyst requires heat (reflux) Reflux involves heating the chemical reaction for a specific amount of time, while continually cooling the vapour produced back into liquid form through a condenser tube into the reaction flask 18M h2so4 catlyst increases yield, and acts as dehydrating agent shifting equilibrium to the right water is a solute that is dissolved in alcohol and carboxylic acid, meaning we can talk about water as concentration reflux is used as heating causes loss of product due to volatility and alcohol is flammable

Answer 13

prevents loss of reagents and products, maximising yield rxn can be perfomed at higher temps increasing ROR improves safety be reducing risk of explosion and inhalation use hotplate or heating mantle to reduce risk of naked flame boiling chips for even mixing of solution

Answer 14

neutralise excess acid (h2so4 or carboylic) with Na2CO3 or NaHCO3 add water to dissolve salts made after neutralising and excess water soluble substances (short chain alcohols) put in separating funnel where denser aqueous substances like water and dissolved substanced are more dense and end up in bottom of the funnel less dense organic layer with esters, and undissolved alcohols and carboxylic acids stays at top add water again and again to dissolved more waste dissolved substances until required distill remaining ester from remaining organic compounds purity of ester can be tested with physical properties like bp, if bp is same or similar to true value, it is pure

Answer 15

soaps are natural, detergents are artificial have a hydrophilic head: which is polar and often charged, interacting with water by ion-dipole or h bonding interactions have a hydrophobic tail: which is non-polar and reacts with alkyl tails via dispersion forces (grease and fat and oil)

Answer 16

an ion with a long non polar alkyl tail and a polar charged carboxylate head usually present as sodium or potassium salts

Answer 17

ion with a non-polar alkyl tail and polar anionic sulfate or benzenesulfanoate head usually present as sodium or potassium salt too harsh for personal hygiene, used in laundry detergent, dishwashing liquid, glass cleaner

Answer 18

ion with a long non-polar alkyl tail and a polar cationic trimethylammonium or quarternary ammonium head usually present as chloride or bromine salts not as harsh as anionic and are effective at removing static friction and tangling used in shampoo and fabric softener are biocidal which means they kill organisms so are used in disinfectants and antiseptics

Answer 19

long non-polar alkyl tail with polar repeating polyethylene glycol head head is uncharged but still polar + ALWAYS ENDS IN ALCOHOL GROUP less lather build up than anionic used in shampoo and conditioner used in front-loading washing machine for low sudsing, also used in some cosmetics

Answer 20

molecule acts on surface of water, hydrophilic head in water, hydrophobic tail out of water (monolayer formation) some surfactant molecules dissolve in water and form micelles which are spherical arrangements (tail inwards favouring dispersion forces, head outward favouring ion-dipole/dipole-dipole with water on the outside)

Answer 21

surfactant molecule dissolves in water aligns so non-polar tail sticks into substance and polar head make ion-dipole forces with water when surface is agitated (scrubbing), small droplets of grease/oil are lifted off dirty surface and suspended in water, this is when incomplete micelles are formed where tail is in substance but it is not spherical in shape as oil droplets become smaller, micelles are formed

Answer 22

entropy and enthalpy changes guide micellisation micelles repel each other by spherical outer surface of negative or positive charges and dispersing throughout the water this is called emulsification --> surfactant is emulsifier, final solution is an emulsion 2 normally immiscible substances (with each other like oil and water) are made to mix with the emulsifier (soap emulsifies oil and water) when water is drained away, oil is taken with it, cleaning the surface

Answer 23

no net release of CO2 co2 emitted by complete combustion is matched by amount of CO2 emitted by original plant during photosynthesis

Answer 24

renewable fuels derived from plant material renewable as plant matter they are made from is easily replenishable in a short timeframe through farming and harvesting

Answer 25

is just ethanol and is called bioethanol as it it formed from the fermentatation of glucose obtained my natural sources such as cellulose or sugarcane to be used as fuel cellulose from plant stalks or sucrose from sugarcane is digested in acid (moderately conc h2so4 or h3po4) to make glucose glucose is fermented to ethanol and purified by distillation max 15% w/v so when spirits or other higher w/v are needed, ethanol is distilled to separate from water to become more pure (at least 95% purity) (repeated multiple times with fractional for highest purity as water and ethanol have similar bp)

Answer 26

carbohydrates converted to alcohols by yeast and other microorganisms alcohol tolerant yeast used to provide zymase enzyme to catalyst rxn temp of 37 degrees maximises yield without damaging yeast anaerobic environment: no oxygen, yeast must be deprived of oxygen, with oxygen it produces co2 and water low pH of 3.7-4.6 by pumping is so2 to prevent pathogens from growing maximum 15% w/v ethanol volume as ethanol kills the yeast

Answer 27

volatile easily forming vapour at room temp flammable: low flashpoint that ignite at a low temperature corrosive or caustic: capable of destroying solid material (can burn tissue)

Answer 28

ppe (lab coat, safety goggles, gloves (immediately disposed of after use) fume cupboard while handling volatile or flammable substances emergency shower and eye washer (irrigate/wash eyes for at least 15 minutes vigourously by holding open eyelids and moving eyes around)

Answer 29

sink drainage contaminates waterways waste is segregated into categories: halogenated organic, non-halogenated organic, inorganic heavy metals, acidic/basic waste acidic/basic neutralise with NaHCO3 to pH around 7 (then waste container) heavy metal: place in heavy metal waste container halogenated: place in halogenated organic waste container (more extensive treatment) non-halogenated: place in non-halogenated organic waste container

Answer 30

report to staff immediately acid and base spills, use large amounts of nahco3 to neutralise (dont use water as it spreads spill) large organic solvent spill, tell staff and evacuate immediately wear face mask to clean

Answer 31

100% pure ethanol is annhydrous but very hard to achieve and distillation is inadequate bioethanol is a fuel additive for motor vehicle use e10 fuel is 10 percent ethanol which is better for environment 25 percent ethanol fuel is used in brazil but blends beyond 10 percent are problematic as they require engine modications to work (expensive and limit market potential)

Answer 32

co2 emitted from combustion same as co2 consumed by photosynthesis of sugarcane addition co2 emitted when transporting ethanol however lower enthalpy of combustion than octane so more is needed to produce same energy (negligible tho) carbon neutral proof --> add photosyntheis fermentation and combustion

Answer 33

mixture of methane and co2 made from organic waste materials previously consdiered useless so its cheap reduces amount of waste in landfill final waste can be used as fertiliser

Answer 34

mixture of esters produced by reacting vegetable oil, palm oil or animal fat with base (undergoes esterification) biodiesel can be used in standard diesel engines so any proportion of biodiesel can be used without engine modifications

Answer 35

renewable carbon neutral burns more cleanly than octane due to partially oxidised nature as it already has oxygen in its structure (reduces release of carbon monoxide-toxic gas)

Answer 36

technology relatively new so very expensive to produce require environmental sacrifices to grow things like sugarcane this reduce agricultural land for other crops involves deforestation for more land destroying habitats and environment pungent fermentation waste must be appropriately disposed harvesting and distillation requires vast amounts of energy made by fossil fuels engine modifications for biofuels could be costly

Answer 37

imperative to develop further not accepted into common usage due to economic and political unviability good alt for future

Mod 7 Flashcards

(61 cards)