module 7 HSC Flashcards

Question

coefficient of fuel in combustion

Answer 1

alcohol -> alkene + H2O catalyst: - conc H2SO4 - heat for primary and secondary - RTP for tertiary

Answer 2

alcohol + HX -> haloalkane + H2O - catalyst: ZnX2 eg. if it was chlorine it would be ZnCl2

Answer 3

HI > HBR > HCl > HF

Answer 4

primary: aldehyde -> carboxylic acid secondary: ketone tertiary: does not occur catalysts: - heat - KMnO4 , acidified potassium permanganate or K2Cr2O7, acidified potassium dichromate - dil H2SO4

Answer 5

primary + secondary: catalyst: heat, acetone solvent haloalkane + dilute NaOH -> alcohol + salt eg. bromoethane + NaOH -> NaBr + ethanol tertiary: tertiary haloalkane + H2O -> tertiary alcohol + HX catalyst: heat

Answer 6

- polar covalent due to the large electronegativity differences

Answer 7

1. as the chain length increases, stronger dispersion forces = higher bp for both 2. alcohols > alkanes - alkanes = non-polar -> only dispersion forces - alcohols = polar -> dispersion, hydrogen bonding, dipole-dipole - harder to break 3. as length increases from 1-8 , alcohol is still greater - but the difference is smaller - proportion of non polar bonds in the alkyl chain and polar bonds diminishes making dispersion forces the dominating force

Answer 8

1 > 2 > 3 - since -OH in primary is the most accessible, dipole-dipole + hydrogen bonding is stronger - crowding of the -OH group also hinders he formation of hydrogen bonds

Answer 9

alcohol + ammonia -> primary amine + water

Answer 10

amine = N and formed from alcohol amide = carbonyl group attached to the N , produced throuh condensation reaction of carboxylic acids

Answer 11

primary amide: carboxylic acid + ammonia -> primary amide + water catalyst: - reflux - DCC - 190 degrees celcius + 4 hours secondary amide: carboxylic acid + primary amide -> secondary amide + water catalyst: - reflux - DCC - 190 degrees celcius + 4 hours tertiary amide: carboxylic acid + secondary amide -> secondary amide + water catalyst: - reflux - DCC - 190 degrees celcius + 4 hours

Answer 12

- break solvent -solvent - break solute - solute - form solute -solvent due to the alcohols polar head, it dissolves readily in polar solvents such as water in comparison to alkanes but less in non-polar solvents such as benzene

Answer 13

- increased carbon chain = increased solubility of alcohols in polar solvents - tertiary > secondary > primary - since tertiary is the most compact with the least accessible Oh it has the weakest dispersion forces and solute-solute interactions

Answer 14

fossil fuels: produced by natural processes on fossilised remains of organisms over significant time - NON RENEWABLE - eg. petroleum advantages: - environmental: extraction reduces pressure on underground oil reservoir to minimise oil seeping - economic: cheap to extract as fossil fuels are found readily - sociocultural: creates new communities where there are more job opportunities disadvantages: - environmental: drilling and fracking damages land, exposing heavy metals and radioactive substances - economic: requires relatively high initial cost and infrastructure - sociocultural: may intrude on scared indigenous land, degrade appeal of natural tourist attractions

Answer 15

a: - environmental: natural gas burns cleaner than wood, haber process saves habitat from conversion into cropland - economic: provide more employment, taxation revenue generated - sociocultural: cultural globalisation with increased international travel, increased availability of electricity boosting community d: - environmental: acid rain from NO2, climate change caused by CO2 production and runaway greenhouse effect - economical: global wealth inequality, automation leads to less jobs in manual labour - sociocultural: degrade appeal of tourist attractions, human rights violations in extreme cases

Answer 16

renewable fuels derived from plant material due to fossil fuels depleting rapidly and the rapid pace of climate change - eg. sugarcane, grains - carbon neutral = no net release of CO2 eg. bioethanol, biogas, biodiesel

Answer 17

a: - renewable - carbon neutral - when bioethanol is used it burns more cleanly which reduced the release of carbon monoxide and mitigates the need for toxic additives d: - relatively new - expensive - requires environmental sacrifices to maximise fuel yield - deforestation which destroys the habitat - lots of energy required evaluation: while there is an absolute imperative to develop biofuels further, they have not been widely accepted into common usage due to their economic and political unviability at this point in time

Answer 18

- produced from fermentation of glucose a: - carbon neutral -> CO2 emitted from complete combustion is matched to the amount of CO2 consumed by sugarcane in photosynthesis d: - requires expensive modifications - additional CO2 is emitted in processing and transportation - ethanol is lower enthalpy of combustion ithan octane but requires more fuel to make the same energy

Answer 19

biological process by which carbohydrates are converted to alcohol by yeasts and other microorgansisms

Answer 20

1. zymase enzyme 2. 37 degree temperature 3. anaerobic environment (deprived of oxygen) 4. low pH (3.7 - 4.6)

Answer 21

6CO2 + 6H2O -> C6H12O6 + 6O2

Answer 22

C6H12O6 -> (zymase) 2C2H5OH + 2CO2

Answer 23

C2H5OH + 3O2 -> 2CO2 + 3H2O

Answer 24

carbonyl group - oxygen is more electronegative than carbon so C-O is polar - has dispersion + dipole - weaker intermolecular forces than alcohols and they lack the ability to have hydrogen bonding - solubility decreases as the chain length decreases

Answer 25

factors that increase delta H of combustion: - not stirring water at the base of the can which is warmer --> stir vigorously with. rod - thermometer resting at the base of the can which may be warmer -> suspend the thermometer in the water with a clamp from the retort stand factors that increase delta H of combustion: - impurities in water so it wont combust well -> change spirit burner - can is too far from flame or has soot so there is insufficient heat transfer -> clean can and move closer - can is too close to the flame so there is insufficient O2 and incomplete combustion occurs -> move further away - heat radiated/conducted from apparatus and surroundings -> turn off fans and use a lid

Answer 26

- polar: presence of two highly electronegative oxygen atoms - has dispersion + hydrogen + dipole - stronger intermolecular forces than alcohols as it has both CO and OH - high boiling points and high solubility (shorter) - the longer the chain, the non-polar portion dominates making it less soluble

Answer 27

polar as the nitrogen is highly electronegative - has both dipole dipole and hydrogen bonding but weaker than an OH bond as the difference i smaller - weaker intermolecular forces than alcohols and carboxylic acids - stronger than alkanes - soluble in water esp short chained - high boiling point than alkane but lower than carboxylic and alcohols tertiary < secondary < primary (more hydrogen bonds) and tertiary does not participate in hydrogen bonds -> lower solubility and boiling point

Answer 28

primary and scondary have hydrogen bnding - all have dipole dipole - strongest intermolecular forces out of all organic compounds due to the unique geometry in the hydrogen bonding - high boiling points smaller amides are more soluble as dispersion forces decrease as molecular weight increases

Answer 29

Materials Safety Data Sheet (MSDS) or Safety Data Sheet (SDS)

Answer 30

- potential hazards - precautions to avoid injury - first aid action plan

Answer 31

- volatile (vapour at rtp) - flammable - corrosive/caustic

Answer 32

personal protective equipment (PPE) - safety goggles - gloves - lab coat - fume cupboard to handle volatile substances - emergency shower + eye washer

Answer 33

C6H6 - ring structure - aromatic - alternating double and single bonds - extremely stable

Answer 34

basically benzene with a hydroxyl group that replaces a hydrogen atom - weakly acidic

Answer 35

-COO - equilibrium reaction alcohol + carboxylic acid ->-< ester + water catalyst: - conc. H2SO4 - reflux

Answer 36

ethyl butanoate = pineapple ethyl ethanoate = nail polish rem

Answer 37

- two polar bonds C-O and C--O - dipole dipole and dispersion forces - lack of hydrogen bonding -> lower boiling point and poor solubility - as the chain increases = stronger dispersion forces - solubility decreases as chain increases and hydrophobic chain dominates

Answer 38

conc H2SO4 increases rate of reaction and acts as a dehydrating agent shifting equilibrium right - heat increases the rate of reaction - boiling chips prompts even boiling and controls boiling

Answer 39

procedure by which flask is continually heated whist vapours eerging from it are guided through a condenser tube which cools the gases and condenses them back into the reaction flask

Answer 40

acts as a catalyst to increase rate of reactions acts as a dehydrating agent to shift the equilibrium to the right

Answer 41

1. prevents loss of reagents and products 2. allows reaction to be performed at a much higher temperature 3. improves safety

Answer 42

1. provides nucleation points for bubbles to promote a smoother boil 2. reduces risk of superheating

Answer 43

surface-active agents which lower the surface tension of a liquid - hydrophilic head - hydrophobic tail = non-polar alkyl tail eg. soaps and detergent which are added to clean non-polar substances from surfaces such as oil and grease

Answer 44

soap = natural detergent = artfiicial

Answer 45

- polar - often charged - interacting with water molecules by ion-dipole interactions and hydrogen bonding

Answer 46

- non-polar - does not interact strongly with water - interacts with other alkyl tails via dispersion forces

Answer 47

ion with a long non-polar alkyl tail and a polar charged carboxylate head - present as sodium/potassium salts hardwater: - precipitates with Mg2+ and Ca2+ to form scum

Answer 48

- ion with long non-polar alkyl tail and polar anionic sulfate head - present as sodium/potassium salts - good lather = dishwashing, laundry detergent - too strong for personal hygiene hardwater: - forms soluble complexes with Mg2+ and Ca2+ - no scum but efficacy decreased --> solved with phosphate buffers

Answer 49

- ion with non-polar alkyl tail and a polar cationic trimethylammonium head - present as chloride or bromide salts - not as harsh as anionic - shampoo and antiseptics, disinfectants - reduces tangling - biocidal - kills microorganisms hardwater: - no effect - positively charge

Answer 50

kills microorganisms

Answer 51

- molecule with non-polar alkyl tail and polar repeating polyethylene glycol head - always end in OH - uncharged head but still polar - less lather - shampoo conditioner hardwater: - no effect, neutral so it doesnt react

Answer 52

impure water that contains Ca2+ and Mg2+

Answer 53

spherical arrangements of surfactant molecules with hydrophobic tails trailing centre and hydrophillic heads facing outwards

Answer 54

- structure: hydrophilic polar head + hydrophobic tail non polar - surfactant dissolves in water - orientation: surfactant molecules align themselves such that the non-polar alkyl tails stick into the substances forming dispersion forces and the polar heads face outwards forming ion dipole forces with the water - agitation: when surface is agitated, through virgourous scrubbing, small droplets of greae are lifted off the surface and momentarily suspended in water where incomplete micelles form with the polar heads facing outwards and on-polar tails sticking to the oil - as oil droplets become smaller complete micelles are formed - micelles repel each other by their spherical outer surface of negative charges and disperse throughout the water - emulsification , electrostatic repulsion stops the oils from coming together, but two immiscible liquids are made to mix by the action of the emulsifier - drained away

module 7 HSC Flashcards

(80 cards)