Organic chemistry Flashcards
What are hydro-carbons
= molecules which only contain carbon and hydrogen atoms
What is a homologous series
= group of organic molecules with similar chemical properties
- all compounds in a homologous series have the same gen. formula
What are functional groups
= atoms responsible 4 characteristic reactions of a particular compound. Members of the same homologous series belong to same f. group.
What are alkanes
= saturated hydrocarbons -> carbon atoms joined by single bonds (c-c)
Alkanes general formula
C(n)H(2n+2)
What are alkenes
= unsaturated hydrocarbons -> some of their carbon atoms are joined by a double bond
(c=c)
What is fractional distillation
= separates a mixture into a number of different parts, called fractions -> substances with high boiling points condense at the bottom and lower boiling point condense on the way to the top
What are boiling points
-> smaller the molecule, smaller the boiling point b/c dec. intermolecular forces b/n molecules t/f dec energy needed 2 break them.
What is viscosity
= measure a fluid’s resistance 2 flow
longer carbon chains = higher viscosity
What is cracking
= breakdown of large hydrocarbon molecules into smaller molecules using a catalyst
What is a catalyst
-> refers 2 a substance used 2 decrease the activation energy in a reaction
What is the cracking method
1) heating mineral-wool soaked in oil with a catalyst, producing a gas
2) oil will likely be a long chain hydrocarbon, the catalyst is heated and not the oil b/c the oil = flammable
3) the product being gaseous suggests we have produced molecules with a smaller size than that of the oil
What is complete combustion
= compounds of hydrogen + carbon only. When burned -
- > carbon oxidises 2 become CO2
- > hydrogen oxidises 2 become H2O
(hydrocarbon + oxygen -> carbon dioxide + water)
What is incomplete combustion
= occurs when supply of air or oxygen is poor. Water is still produced but carbon monoxide and carbon are produced instead of co2
(hydrocarbon + oxygen -> c/co/co2 + water)
What is a substitution reaction
= 1 atom swapped with another
Alkanes undergo a substitution reaction with halogens in the presence of UV light
(alkanes + hydrogen –(light)–> alkanes)
What is an addition reaction
= The presence of c=c bond allows 4 inc. complex reactions 2 take place.
Alkanes can react with dif. types of chemicals during addition reaction
Addition reaction: Bromine water
- Bromine water use 2 distinguish alkanes + alkynes
- X change when alkane added to water
- Bromine water becomes colourless from orange-brown when mixed with an alkene
Addition reaction: Hydrogenation
- Alkenes can react with dif types of chemicals during addition reactions
(Alkene + hydrogen –(catalyst)–> Alkane)
-> needs a catlayst
Addition reaction: Hydration
= need 2 be temp of 300 degrees C + catalyst
Alkene + water(steam) –(300degC, catalyst)–> alcohol
How to produce ethanol
1) hydration
2) fermentation
(look in notes 4 pos + neg of each)
