Chapter 19 hydrocarbon Flashcards
What are hydrocarbons
contains hydrogen and carbon
Characteristic of homologous series
Same general formula
Similar chemical properties
Gradation in physical properties
Alkanes properties
Contains only c-c bond
general formula of cnH2n+2
Differ by -ch2- unit
Similiar chemical properties
Types of alkanes
Methane (ch4)
Ethane C2h6
propane c3h8
butane c4h10
What are saturated compounds
Only contain c-c carbon atoms
What are the trends in physical property of alkane
(down the series) Melting and bp increase
( have covalent compounds and simple molecular structure
More C atom larger molecular mass, larger amount of energy needed to overcome intermolecular foa)
become more viscious
denser
less flammable
Reactions of alkanes
Combustion
Substitution ( presence of ultra violet )
alkene properties
general formula of cnh2n
Same functional group
c=c bond
diff by -ch2-
example of alkenes
Methene
Ethene c2h4
propene c3h6
butene c4h8
alkene reactions
combustion
addition of hydrogen (150oC, nickel catalyst, vegetable oil to make solid margarine) (alkene to alkane)
Addition of bromine ( room temperature, The reaction is a chemical test for the presence of unsaturated
hydrocarbons, form 1,2 dibromoethane)
Addition of steam ( alkene to alcohol, 300oC, 60 atm, phosphoric(V) acid (H3PO4) as catalyst)
Whhat is test between alkane and alkene
Add bromine to alkane and alkene
Alkene (unsaturated hydrocarbon): Reddish-brown aqueous bromine turns colourless.
Alkane (saturated hydrocarbon): Reddish-brown aqueous bromine remains unchanged /
reddish-brown
What used to Manufacturing of Alkenes and Alkanes?
Catalytic Cracking
what is Catalytic Cracking
Cracking is a process where the larger hydrocarbons molecules, usually alkanes are broken
down into smaller hydrocarbon molecules by heat and in the presence of catalyst.
Conditions of catalytic cracking
