isomers/ naming / halogens+alks

Question 1

isomers

Answer 1

compounds with same molecular formula but different structural/ displayed formula

Question 2

chain isomers

Answer 2

the carbon atoms are arranged in diff orders leading to branched chains
- similar chem properties
- diff physical properties

Question 3

positional isomers

Answer 3

the functional group can be in different positions along the main hydrocarbon chain
- similar chemical properties
- different physical properties

Question 4

chain isomers bp

Answer 4

molecules that are less branched can pack closer so have stronger intermolecular forces
- higher boiling point

Question 5

longer carbon chain in relation to isomers

Answer 5

longer chain = more isomers

Question 6

naming alkanes

Answer 6

numbers = position of side chains - separate by commas and separate from word by dash
start = no. side chains (di, tri, tetra, penta)
middle = side chains count carbons and end in -yl
end = longest carbon chain

Question 7

naming alkenes

Answer 7

same as alkanes
give position of double bond lowest number position
put number in middle of alkene (but - 1 - ene)
each side chain position is based on the direction of the double bond position

Question 8

alkane vs alkene reactivity

Answer 8

alkane - low reactivity
alkene - high reactivity
due to the presence of the double C=C bond in alkenes makes them more reactive

Question 9

halogen prefixes

Answer 9

bromo-
chloro-
iodo-
if multiple use di, tri, tetra, penta

Question 10

alkenes with halogens observation

Answer 10

bromine water goes orange to colourless

Question 11

alkanes with halogens observation

Answer 11

bromine water remains orange (no reaction at room temp)

Question 12

alkene + halogen reaction

Answer 12

ADDITION
condition - room temp (very reactive)
double bond breaks and each halogen goes to each carbon - becomes alkane

Question 13

alkane + halogen reaction

Answer 13

SUBSTITUTION
conditions - UV light (inert)
a halogen atom takes place of hydrogen atom in the alkane and a hydrogen halogen is created

Question 14

alkanes / alkenes as fuels

Answer 14

• short chain alkanes are used as fuels
• alkenes don’t combust completely as often and burn sootier so arent used as fuel

Question 15

complete combustion of hydrocarbons

Answer 15

hydrocarbon + oxygen > water + carbon dioxide
(oxidation)
(releases CO2 - greenhouse gas)

Question 16

incomplete combustion of hydrocarbons

Answer 16

hydrocarbon + oxygen
> carbon monoxide + water
or> carbon + water
(soot can dim air and trigger asthma)
(carbon monoxide is toxic)

Question 17

bunsen - complete / incomplete combustion

Answer 17

closed - yellow flame - incomplete combustion
open - blue flame - complete