general shit

Question 1

What type of addition can alkenes undergo

Answer 1

electrophilic addition

Question 2

what is an electrophile

Answer 2

electrophiles are electron pair acceptors which are attracted to areas of high electron density

Question 3

why are electrophiles attractred to carbon double bonds

Answer 3

the carbon double bonds have high electron density

Question 4

what happens to the carbon double bonds ion electrophilic addition

Answer 4

the double bond opens up and atoms get added to the carbon atoms

Question 5

what reaction with alkenes produces an alkane

Answer 5

hydrogenation

Question 6

what are conditions for hydrogenation

Answer 6

alkenes will react with hydrogen and a nickel catalyst at 150 degrees

Question 7

what forms when halogens react with alkenes

Answer 7

dihaloalkanes

Question 8

what reaction with alkenes produces alcohols

Answer 8

steam hydration

Question 9

conditions for steam hydration

Answer 9

hydrated by steam at 300 degrees
pressure of 60-70 atm
phosphoric acid catalyst
reversible reactions cause low yeld unlessyou recycle

Question 10

why are alcohols polar

Answer 10

the hydroxyl group is electronegative which pulls electron density away from the carbon atom

Question 11

why are alcohols siluble in water

Answer 11

the partially positive hydrogen in the OH bond can form hydrogen bonds with oxygens from neighbouring molecules. hydrogen bonds are formed between the oxygens in water which lets alcohols mix freely

Question 12

what happens to the solubility of alcohols as they increase in size

Answer 12

solubility decreases as most of the molecule is non-polar. causing less attraction for the for the H2O molecules

Question 13

what reactions do alcohols have to form haloalkanes

Answer 13

alcohols can react with compounds containing halide ions in a substitution reaction causing the OH group to be replaces with a halogen forming a haloalkane

Question 14

how do alcohols become alkenes

Answer 14

alcohols become alkenes through dehydration reactions

Question 15

what is a dehydration reaction

Answer 15

eliminating water from alcohols in an elimination reaction

Question 16

how does a dehydration reaction happen

Answer 16

the alcohol is mixed with an acid catalyst (sulfuric or phosphoric, both concentrated) then heated

Question 17

where does the water come from in dehydration reactions

Answer 17

the water molecule is made up from the hydrixyl group and a hydrogen atom that was bonded to a carbon atom adjacent to the hydroxyl carbon

Question 18

what does burning alcohol in a plentiful supply of oxygen cause

Answer 18

its causes combustion of the alcohol

Question 19

what are products of combustion

Answer 19

CO2 and H2O

Question 20

what are primary alcohols oxidied to?

Answer 20

primary alcohols are oxidised to aldehydes adn then to carboxylic acids

Question 21

what are secondary alcohols oxidised to?

Answer 21

secondary alcohols are oxidised to ketones only

Question 22

what are tertiaty alcohols oxidised to

Answer 22

they dont oxidise

Question 23

how are aldehydes formed from primary alcohols

Answer 23

aldehydes are formed by gently heating excess alcohol with a controlled amount of oxidising agent in a distilling apparatus

Question 24

how are carboxylic acids formed from primary alcohols

Answer 24

the alcohol is mixed with excess oxidising agent and heated under reflux

Question 25

how are ketones formed from secondary alcohols

Answer 25

reflux the alcohol with acidified potassium dichromate

Question 26

what is the only way to oxidise a tertiary alcohol

Answer 26

burn the fucker

Question 27

what are stereoisomers

Answer 27

stereoisomers have the same structureal formula but are arranged differently in space

Question 28

what causes stereoisomers

Answer 28

restricted rotation in the double carbon bond

Question 29

what are z-isomers

Answer 29

a z isomer is when it has the same groups above or below the double bond

Question 30

what is an E isomer

Answer 30

and E isomer is when the same groups are positioned accross the double bond

Question 31

what is a sigma bond

Answer 31

a sigma bond is formed when two S orbitals overlap each other
the two s orbitals overlap in a striaght line, this gives the highest possible electron density between the two nuclei. this is a single covalent bond

Question 32

what is a pi bond

Answer 32

a pi bond is formed by the sideways overlap of two adjacent p orbitals
it has 2 parts to it, one above and one below the the moloecular axis due to the dumbell shape of the p oribtal,

Question 33

why are pi bonds weaker

Answer 33

pi bonds are weaker than sigma bonds because the electron density is spread out above and below the nuclei. this means that the electrostatic attraction between the nuclei and the shared pair of electrons is weaker, therfore pi bonds have a relatively low bond enthalpy

Question 34

why are alkenes reactive

Answer 34

this is because of the double bond. the double bond contains high electron density (2 lone pairs) causing electrophiles to be attractred to it. it also contains pi bonds which have their electrons above and below the rest of the molecule making it likely to be attacked by electrophiles

Question 35

def of a covalent bond

Answer 35

a covalent bond is the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 36

def of average bond enthalpy

Answer 36

the enrgy required to break a covalent bond

Question 37

what is a dative covalent bond

Answer 37

this is where both electrons come from one atom

Question 38

relative isotopic mass definition

Answer 38

mass compared with 1/12th mass of carbon-12

Question 39

relative atomic mass def

Answer 39

weighted mean mass
compared with 1/12th mass of carbon-12

Question 40

empirical formula

Answer 40

simplest whole number ratio of atoms in a molecule

Question 41

products of incomplete combustion

Answer 41

carbon dioxide
water
pure carbon
carbon monoxide
hydrocarbons